In my last segment, I argued that the Long Peace is really a composite of four relationships, and that the most important of these — Cold War stability — is either the result of factors that will not persist, or results from the ideological nature of the contest in ways that have yet to be carefully analyzed. Perhaps because of the complexity and possible irrelevance of the Cold War, attention has increasingly shifted to the liberal peace as a guide to the future.

The observation that developed democracies seldom fight each other is arguably the most important discovery in the recent study of international relations. Yet, before we credit democracy with peace, we must consider the possibility that whatever causes democracy is itself responsible for the relative absence of conflict among liberal states.[1] Unfortunately, researchers have yet to agree on a canonical explanation for democracy, making it difficult to determine whether the causes of democracy might themselves be the causes of peace. What I outline below is thus speculative, only partly backed by evidence and by logic.

As I noted in the last segment, peace requires that no nation perceive a benefit from acting aggressively. It is tempting to believe that democracy could accomplish this. Yet, while western liberal democracies are certainly “nice” to each other, there are several reasons to wonder whether this is due to democracy, per se. We already know that democracies are not more peaceful monadically. In addition, Mousseau shows that only rich democracies benefit from democratic peace. If democratic peace only works among satisfied states, then perhaps it is these states’ circumstances, rather than their politics, that leads these nations to cooperate. My own work suggests that countries with similar interests are much less likely to fight, independent of regime type. This may explain the effect of democratic

peace by itself, though this claim is disputed by others. In a forthcoming paper, I also show that the strength of the democratic peace seems to be declining as the number and diversity of democracies grows. Researchers have begun to distinguish between

“good” (i.e. liberal) and “bad” democracies (Zakaria). It will come as no surprise to readers if democracy in

the Middle East and North Africa produces regimes that are not Western friends. Finally, the democratic peace has proven surprisingly resistant to coherent explanation. As Charles Lipson quips “We know it works in practice. Now we have to see

if it works in theory!

There remains something intuitive about the claim that democracy and peace are related. Yet, this may be because democracy comes from peace, rather than producing it. Indeed, democracy alone among domestic political systems requires peace as a prerequisite. As soon as the loser in an election takes up arms to reassert

political success, democracy is in jeopardy. Domestically, democracy requires that political losers prefer defeat to the use of force. The same must be true internationally of course in order to maintain stability.

A compatibility of interests helps to account for democracy within and the lack of conflict between polities. A society

in which the population lacks a critical consensus about policies is unlikely to form or survive as a democracy. Tensions between policy preferences should tend to either prevent democratization or destroy it, as political losers cannot accept defeat on peaceful terms. This is the story of Weimar Germany and indeed of the U.S. Civil War. If, in

addition, democracy tends to form domestically only when populations are centrist in their preferences, then the “median” or “pivotal” actor in these centrist democracies will tend to be more similar than the pivotal preferences among autocracies (given the effect of majoritarian rule). Democracy will be associated with moderate foreign policies, not because

democracy causes moderation, but because moderation causes democracy.

At the same time, nations fight over more than just policy differences. Tangible material goods can also form the basis for conflict. Here, it is economic development that appears to play a crucial role. In published and unpublished research, I have shown that developed states are much less likely to fight over territory (though no less prone to dispute policy

differences). The rising cost of labor associated with economic development has meant that most modern nations prefer to buy the fruits of territory rather than seek to conquer (steal) land directly. Economic development also just happens to be the most widely used and accepted predictor of domestic political liberalization. Prosperous, which just happen to cluster geographically, are both much less prone to fight over where their borders ought to be and much more likely to be democratic. The increasing productivity of labor and the inefficiency of coercion make it much more appealing to govern societies through consent, rather than through coercion. Conquest, and tyranny, no longer pay. This implies that development leads both to a decline in territorial conquest and to a rise in democracy.

Growth in the number of democracies in the world may provide enough impetus to sustain and even broaden the Long Peace, if the causes of peace lie largely in political liberalization. Systemic liberal peace advocates have suggested exactly this relationship. However, stable democracy has been slow to materialize in many regions; the shift to majoritarian rule has not coincided with the consolidation of liberal norms or institutions often thought to be the key factors in promoting liberal international peace. Similarly, there is some evidence that the democratic peace is not as robust after the Cold War. If instead development causes a shift away from territorial aggression, then there is reason for hope in the very processes that appear to be leading to a multipolar world. China, India, and other developing nations may join the West in eventually eschewing conquest as a viable foreign policy option.

Where tensions will remain is in the area of the nature and content of global and regional governance. Ironically, as the world becomes more integrated, the stakes in having one’s way in the world have become much higher. Without unipolarity, the world’s leading nations must find new ways to compromise and dissect differences, rather than allowing them to accumulate into indigestible omnibus disputes. Though the work on international institutions shows relatively little

pacific effect, their greatest impact may be yet to come.

***

Erik Gartzke is an associate professor of political science at UC San Diego. Gartzke’s primary area of study involves the impact of information and institutions on war and peace. He applies bargaining theory, rational choice institutional theory, concepts of power and social identity, and statistical analysis to four substantive areas of interest: 1) The liberal peace, 2) international institutions, 3) diplomacy, and 4) the system overall.

In my previous two blog segments, I outlined an argument that economic development, and the management of international interests, are the primary causes of the Long Peace. This segment deals with the final two empirical relationships of the Long Peace, the fact that most of the world

has benefitted only obliquely from a “Pax Americana,” or

Long Peace.

People, groups and nations fight over either tangible, real goods (territory) that are difficult to divide up, or intangible goods like policy that may be partially public (more than one actor can share in the same benefit). These are not necessarily attributes of contests, but of the interests of actors in relation to a contest. A coalition of states ejected Saddam Hussein from Kuwait, while the Iraqis fought alone in part because each side fought with different objectives in mind. For Iraq to build a coalition, it would have had to agree to

split up the oil riches of Kuwait. The U.S. had little difficulty with a coalition, since this meant “sharing” things like the principle of territorial integrity, collective security, or Middle East stability.

The fact

that democracies are no less likely to use force in general reflects the fact that they fight non-democracies more often than non-democracies fight each other. It is tempting, if difficult, to explain this behavior with regime type, but very easy to explain it in terms of development. Democracies — mostly prosperous, advanced societies — are fighting with the poor more often than poor nations — typically non-democracies — fight each other in large part because they can. Development makes it is easier to project power, increasing the number of states that a nation can physically fight. Poor states seldom fight anyone, if for no other reason than that they are not physically capable of doing so. A

peace between Rwanda and Belize is not, and never has been, remarkable. Yet, while development makes states better able to fight far from home, it also gradually reduces their interest in doing so for the purpose of direct material gain. Developed states face economic conditions that mean they much prefer to buy, rather than conquer. In a study with Dominic Rohner, we show that imperialism initially waxed with power projection capabilities, and then waned.

In contrast, if prosperous states prefer to buy their goods rather than fight for them, they are fully ready to fight to assert preferred policies. The bulk of developed/non-developed conflict can be explained in terms of Western nations attempting to impose their preferred policies on the developing world. Sometimes, these interventions have a normative flavor (Kosovo, Kuwait, Somalia), but the exceptions and inconsistencies suggest that these have less to do with principle than self-interested. Instability in the developing world is ignored if it is likely to remain localized (Rwanda, Congo). Western interest is piqued when and if there is the danger of spillover to important economic or political interests (oil, trade, etc).

The decline of territorial conflict in the developed world (associated with democracies), and a large scale consensus about

international politics, has led to peace in Europe and elsewhere. In other regions, peace has been maintained by default, either because nations were incapable of projecting power (Africa, parts of Latin America), or because differences over policy were not easily remedied by war (the U.S. and the Soviet Union, China). There is no reason to believe that

Europe will see a return of war in future decades. Similarly, Russia is in no position to assert its dissatisfaction with world affairs more than indirectly, in peripheral disputes.

China alone remains a major power capable of

attempting to thwart or even upend important aspects of the prevailing order. While there are increasing calls to contain China, it may be prove more fruitful to ensure that China’s interests are addressed and that it prefers some version of the status quo to a costly transformation.

The one place most likely to see more war in the future is the one least touched by the Long Peace. Broadening prosperity will see an increasing number of nations willing and able to pursue old grudges that previously were outside their grasp. At the same time, multipolar politics and a declining hegemon will make it more difficult to police the global commons as effectively as in the past, particularly given the increasing capabilities of developing states. We see this today in talk of a nuclear Iran and in U.S. efforts to

co-opt nations such as India. Coming decades may well reveal a race between the unraveling of an existing international hierarchy and growing international power and prosperity generally. If developing nations are quick to evolve economically, there will be little time for their leaders to act to address territorial disputes before territory becomes redundant in a modernizing world. If instead these nations stagnate economically, numerous reasons will appear to seek to revise their borders and reassert authority over lands that are tempting and tractable only temporarily.

Finally, the effects of development on peace assume that the labor costs of occupation will remain high for developed societies. Western nations (the United States in particular) have begun to automate their militaries. If pilotless drones or ground vehicles substitute capital for labor in sufficient numbers, then territorial conquest may again prove profitable. In the movie Terminator, warlike machines take over the world. It may soon be possible, if no less horrible, that part of the planet will be dominated by predatory machines (run remotely by human beings), created not by evil computers or automated empires, but by the

citizens of the very democracies that we look up to today for humanity, civilization, and peace. Those who believe that democracy prevents states from doing evil abroad should look to history.

***

Erik Gartzke is an associate professor of political science at UC San Diego. Gartzke’s primary area of study involves the impact of information and institutions on war and peace. He applies bargaining theory, rational choice institutional theory, concepts of power

and social identity, and statistical analysis to four substantive areas

of interest: 1) The liberal peace, 2) international institutions, 3) diplomacy, and 4) the system overall.

Everyone knows that the expectation of any event is equal to its probability times the consequences which ensue

if it occurs. (E = p x c).

A rather improbable event, therefore, can still be worrisome if its consequences are severe. Even if the probability of major war has declined, we cannot neglect war’s possible occurrence. After all, the probability of war in 1914 was quite low, though it still took place.

First, a possible glitch in the decline of major war theory is that when one great power rises to challenge a leader, war is more likely. Of the 13 cases of such challenge since 1500, all but three ended in major conflict. Perhaps the reason for peace since 1945 is that (except for the Cold War) there have been no cases of one Great Power threatening to pass the hegemonic leader in charge. Despite Japan’s surge in the 1980s, it posed no such threat. Ernest May shows that when the United States surpassed Britain in 1890s, the British acceded to all American demands, on the Venezuelan boundary, the independence of Panama and the Panama Canal, and the growing size of the

US Navy. [May Aspen paper, (Summer, 2006)]. In 2020 the United States is unlikely to concede all Chinese claims (to the islands in South China Sea, the absorption of Taiwan, and an unlimited increase in Chinese armaments). What then?

Second, having recently surveyed the events of the two World Wars, a number of historians and political scientists concluded that leadership or the

lack thereof can make a huge difference in the occurrence of truly

improbable events. [See E. May, R. Rosecrance and Z. Steiner, eds. “History and Neorealism” (2010)] The First World War was in the parlance of the time, “the war to end wars.” Neville Chamberlain shared that conclusion but nonetheless opted for war against Germany on September 3, 1939. Even Hitler wanted to avoid general war, picking individual opponents as one plucks artichoke leaves, one after other; at the same time, if frustrated, he would attack even

bigger countries, leading to war with most of the world. Recent data on Chinese Poliburo debates reveals in 1950 that Mao Zedong was one of the few members who would willingly intervene in the Korean War; others including some military leaders preferred to hold back. Mao’s emotional predominance, dictated the outcome. Similar information indicates the majority of the Ex-Com decision-makers in 1962 initially favored bombing or invasion of Cuba, with all of the consequences that might have

involved. In 1941 Franklin Roosevelt was willing to push Japan (perhaps toward war) in order to prevent it joining with Germany in the attack on Russia. Inexorable historical trends did not chart leaders’ conclusions. In many if not most of these episodes, a leader acted differently from his associates and from historical trends, with perilous consequences for all concerned.

Steven Pinker rightly says that the probability of major war has been “decimated” but that strictly means reduced by one-tenth, and even if more greatly, we should not be consoled by historical tendencies that no leadership will necessarily follow or even be aware of.

This means that rather than relying on historical trends to protect the world, we have in fact to do something about it. I have suggested a large amalgamation of Europe and the United States to create a positive overbalance of power which will in the end attract China to play an

important role in a wider world.

by Erik Gartzke

In my last segment, I argued that the Long Peace is really a composite of four relationships, and that the most important of these — Cold War stability — is either the result of factors that will not persist, or results from the ideological nature of the contest in ways that have yet to be carefully analyzed. Perhaps because of the complexity and possible irrelevance of the Cold War, attention has increasingly shifted to the liberal peace as a guide to the future.

The observation that developed democracies seldom fight each other is arguably the most important discovery in the recent study of international relations. Yet, before we credit democracy with peace, we must consider the possibility that whatever causes democracy is itself responsible for the relative absence of conflict among liberal states.[1] Unfortunately, researchers have yet to agree on a canonical explanation for democracy, making it difficult to determine whether the causes of democracy might themselves be the causes of peace. What I outline below is thus speculative, only partly backed by evidence and by logic.

As I noted in the

last segment, peace requires that no nation perceive a benefit from acting aggressively. It is tempting to believe that democracy could accomplish this. Yet, while western liberal democracies are certainly “nice” to each other, there are several reasons to wonder whether this is due to democracy, per se. We already know that democracies are

not more peaceful monadically. In addition, Mousseau shows that only rich democracies benefit from democratic peace. If democratic peace only works among satisfied states, then perhaps it is these states’ circumstances, rather than their politics, that leads these nations to cooperate. My own work suggests that countries with similar interests are much less likely to

fight, independent of regime type. This may explain the effect of democratic peace by itself, though this claim is disputed by others. In a forthcoming paper, I also show that the strength of the democratic peace seems to be declining as the number and diversity of democracies grows. Researchers have begun

to distinguish between “good” (i.e. liberal) and “bad” democracies (Zakaria). It will come as no surprise to readers if democracy in the Middle East and North Africa produces regimes that are not Western friends. Finally, the democratic peace has proven surprisingly resistant to coherent explanation. As Charles Lipson quips “We know it works in practice. Now we have to see if it works in

theory!

There remains something intuitive about the claim that democracy and peace are related. Yet, this may be because democracy comes from peace, rather than producing it. Indeed, democracy alone among domestic political systems requires peace as a prerequisite. As soon as the loser in an election takes up arms to reassert political success, democracy is in jeopardy.

Domestically, democracy requires that political losers prefer defeat to the use of force. The same must be true internationally of course in order to maintain stability.

A compatibility of interests helps to account for democracy within and the lack of conflict between polities. A society in which the population lacks a critical consensus about policies is unlikely to form or survive as a democracy. Tensions between policy preferences should tend to either prevent democratization or destroy it, as

political losers cannot accept defeat on peaceful terms. This is the story of Weimar Germany and indeed of the U.S. Civil War. If, in addition, democracy tends to form domestically only when populations are centrist in their preferences, then the “median” or “pivotal” actor in these centrist democracies will tend to be more similar than the pivotal preferences among autocracies (given the effect of majoritarian rule). Democracy will be associated with moderate foreign policies, not because democracy causes moderation, but because moderation causes democracy.

At the same time, nations fight over more than just policy differences. Tangible material goods can also form the basis for conflict. Here, it is economic development that appears to play a crucial role. In published and unpublished research, I have shown that developed states are much less likely to fight over territory (though no less prone to dispute policy differences). The rising cost of labor associated with economic development has meant that most modern nations prefer to buy the fruits of territory rather than seek to conquer (steal) land directly. Economic development also just happens to be the most widely used and accepted predictor of domestic political liberalization. Prosperous, which just happen to cluster geographically, are both much less prone to

fight over where their borders ought to be and much more likely to be democratic. The increasing productivity of labor and the inefficiency of coercion make it much more appealing to govern societies through consent, rather than through coercion. Conquest, and tyranny, no longer pay. This implies that development leads both to a decline in territorial conquest and to a rise in democracy.

Growth in the number of democracies in the world may provide enough impetus to sustain and even broaden the Long Peace, if the causes of peace lie largely in political liberalization. Systemic liberal peace advocates have suggested exactly this relationship. However, stable democracy has been slow to materialize in many regions; the shift to majoritarian rule has not coincided with the consolidation of liberal norms or institutions often thought to be the key factors in promoting liberal international peace. Similarly, there is some evidence that the democratic peace is not as robust after the Cold War. If instead development causes a shift

away from territorial aggression, then there is reason for hope in the very processes that appear to be leading to a multipolar world. China, India, and other developing nations may join the West in eventually eschewing conquest as a viable foreign policy option.

Where tensions will remain is in the area of the nature and content of global and regional governance. Ironically, as the world becomes more integrated, the stakes in having one’s way in the world have become much higher. Without unipolarity, the world’s leading nations must find new ways to compromise and dissect differences, rather than allowing them to accumulate into indigestible omnibus disputes. Though the work on international institutions shows relatively little pacific effect, their greatest impact may be yet to come.

***

Erik Gartzke is an associate professor of political science at UC San Diego. Gartzke’s primary area of study involves the impact of information and institutions on war and peace. He applies bargaining theory, rational choice institutional theory, concepts of power and social identity, and statistical analysis to four substantive areas of interest: 1) The liberal peace, 2) international institutions, 3) diplomacy, and 4) the system overall.

by Erik Gartzke

In my previous two blog segments, I outlined an argument that

economic development, and the management of international interests, are the primary causes of the Long Peace. This segment deals with the final two empirical relationships of the Long Peace, the fact that most of the world has benefitted only obliquely from a “Pax Americana,” or Long Peace.

People, groups and nations fight over either tangible, real goods (territory) that are difficult to divide up, or intangible goods like policy that may be partially public (more than one actor can share in the same benefit). These are not necessarily attributes of contests, but of the interests of actors in relation to a contest. A coalition of states ejected Saddam Hussein from Kuwait, while the Iraqis fought alone in part because each side fought with different objectives in mind. For Iraq to build a coalition, it would have had to agree to split up the oil riches of Kuwait. The U.S. had little difficulty with a coalition, since this meant “sharing” things like the principle of territorial integrity, collective security, or Middle East stability.

The fact that democracies are no less likely to use force in general reflects the

fact that they fight non-democracies more often than non-democracies fight each other. It is tempting, if difficult, to explain this behavior with regime type, but very easy to explain it in terms of development. Democracies — mostly prosperous, advanced societies — are fighting with the poor more often than poor nations — typically non-democracies — fight each other in large part because they can. Development makes it is easier to project power, increasing the number of states that a nation can physically fight. Poor states seldom fight anyone, if for no other reason than that they are not physically capable of doing so. A peace between Rwanda and Belize is not, and never has been, remarkable. Yet, while development makes states better able to fight far from home, it also gradually reduces their interest in doing so for the purpose of direct material gain. Developed states face economic conditions that mean they much prefer to buy, rather than conquer. In a study with Dominic Rohner, we show that imperialism initially waxed with power projection capabilities, and then waned.

In contrast, if prosperous states prefer to buy their goods rather than fight for them, they are fully ready to fight to assert preferred policies. The bulk of developed/non-developed conflict can be explained in terms of Western nations attempting to impose their preferred policies on the developing world. Sometimes, these interventions have a normative flavor (Kosovo, Kuwait, Somalia), but the exceptions and inconsistencies suggest that these have less to do with principle than self-interested. Instability in the developing world is ignored if it is likely to remain localized (Rwanda, Congo). Western interest is piqued when and if there is the danger of spillover to important economic or political interests (oil, trade, etc).

The decline of territorial conflict in the developed world (associated with democracies), and a large scale consensus about international politics, has led to peace in Europe and elsewhere. In other regions, peace has been maintained by default, either because nations were incapable of projecting power (Africa, parts of Latin America), or because differences over policy were not easily remedied by war (the U.S. and the Soviet Union, China). There is no reason to believe that Europe will see a return of war in future decades. Similarly, Russia is in no position to assert its dissatisfaction with world affairs more than indirectly, in peripheral disputes. China alone remains a major power capable of attempting to thwart or even upend important aspects of

the prevailing order. While there are increasing calls to contain China, it may be prove more fruitful to ensure that China’s interests are addressed and that it prefers some version of the status quo to a costly transformation.

The one place most likely to see more war in the future is the one least touched by the Long Peace. Broadening prosperity will see an increasing number of nations willing and able to pursue

old grudges that previously were outside their grasp. At the

same time, multipolar politics and a declining hegemon will make it more difficult to police the global commons as effectively as in the past, particularly given the increasing capabilities of developing states. We see this today in talk of a nuclear Iran and in U.S. efforts to co-opt nations such as India. Coming decades may well reveal a race

between the unraveling of an existing international hierarchy and growing international power and prosperity generally. If developing nations are quick to evolve economically, there will be little time for their leaders to act to address territorial disputes before territory becomes redundant in a modernizing world. If instead these nations stagnate economically, numerous reasons will appear to seek to revise their borders and reassert authority over lands that are tempting and tractable only temporarily.

Finally, the effects of development on peace assume that the labor costs of occupation will remain high for developed societies. Western nations (the United States in particular) have begun to automate their militaries. If pilotless drones or ground vehicles substitute capital for labor in sufficient numbers, then territorial conquest may again prove profitable. In the movie Terminator, warlike machines take over the world. It may soon be possible, if no less horrible, that part of the planet will be dominated by predatory machines (run remotely by human beings), created not by evil computers or automated empires, but by the citizens of the very democracies that we look up to today for humanity, civilization, and peace. Those who believe that democracy prevents states from doing evil abroad should look to history.

***

Erik Gartzke is an associate professor of political science at UC San Diego. Gartzke’s primary area of study involves the impact of information and institutions on war and

peace. He applies bargaining theory, rational choice institutional theory, concepts of power and social identity, and statistical analysis to four substantive areas of interest: 1) The liberal peace, 2) international institutions, 3) diplomacy, and 4) the

system overall.

by Richard Rosecrance

Everyone knows that the expectation of any event is equal to its probability

times the consequences which ensue if it occurs. (E = p x c).

A rather improbable event, therefore, can still be worrisome if its consequences are severe. Even if the probability of major war has declined, we cannot neglect war’s possible occurrence. After all, the probability of war in 1914 was quite low, though it still took place.

First, a possible glitch in the decline of major war theory is that when one great power rises to challenge a leader, war is more likely. Of the 13 cases of such challenge since 1500, all but three ended in major conflict. Perhaps the reason for peace since 1945 is that (except for the Cold War) there have been no cases of one Great Power threatening to pass the hegemonic leader in charge. Despite Japan’s surge in the 1980s, it posed no such threat. Ernest

May shows that when the United States surpassed Britain in 1890s, the British acceded to all American demands, on the Venezuelan boundary, the independence of Panama and the Panama Canal, and the growing size

of the US Navy. [May Aspen paper, (Summer, 2006)]. In 2020 the United States is unlikely to concede all Chinese claims (to the islands in South China Sea, the absorption of Taiwan, and an unlimited increase in Chinese armaments). What then?

Second, having recently surveyed the events of the two World Wars, a number of historians and political scientists concluded that leadership or the lack thereof can make a huge difference in the occurrence of truly improbable events. [See E. May, R. Rosecrance and Z. Steiner, eds. “History and Neorealism” (2010)] The First World War was in the parlance of the time, “the war to end wars.” Neville Chamberlain shared that conclusion but nonetheless opted for war against Germany on September 3, 1939. Even Hitler wanted to avoid general war, picking individual opponents as one plucks artichoke leaves, one after other; at the same time, if frustrated, he would

attack even bigger countries, leading to war with most

of the world. Recent data on Chinese Poliburo debates reveals in 1950 that Mao Zedong was one of the few members who would willingly intervene in the Korean War; others including some military leaders preferred to hold back. Mao’s emotional predominance, dictated the outcome. Similar information indicates the majority of the Ex-Com decision-makers in 1962 initially favored

bombing or invasion of Cuba, with all of the consequences that might have involved. In 1941 Franklin Roosevelt was willing to push Japan (perhaps toward war) in order to prevent it joining with Germany in the attack on Russia. Inexorable historical trends did not chart leaders’ conclusions. In many if not most of these episodes, a leader acted differently from his associates and from historical trends, with perilous consequences for all concerned.

Steven Pinker rightly says that the probability of major war has been “decimated” but that strictly means reduced by one-tenth, and even if more greatly, we should not be consoled by historical tendencies that no leadership will necessarily follow or even be aware of.

This means that rather

than relying on historical trends to protect the world, we have in fact to do something about it. I have suggested a large amalgamation of Europe and the United States to create a positive overbalance of power which will in the end attract China to play an important role in a wider world.

Like the other contributors to this conversation, I agree with the statement attributed to Yogi Berra that predictions are hard, especially about the future. No responsible person can predict with certainty whether the Long Peace among great powers and developed states will persist. And because we can witness the unfolding of only one universe one time, any statement of probability can be no more than a statement the theorist’s level of subjective confidence.

Still, that level of confidence can be justified to varying degrees, and it seems to me the quantitative trends underlying The Long Peace (nicely superimposed into a single graph by Allan Dafoe in his introduction) reflect genuine changes in the international system. That is, they are not just a gambler’s lucky streak that is sure to run out, an artifact of the way that wars and their human

costs are counted, or a

temporary lull in an inexorable cycle. As such they support a reasonable degree of confidence that The Long Peace will persist (subject to a class of exceptions I will present at the end of this essay).

None of the reasons to dismiss the trends underlying The Long Peace strike me as sound. The wisecracks about the man plummeting off the skyscraper shouting “So far so good!” and the turkey on the eve of Thanksgiving celebrating the 364-day period of coexistence between humans and turkeys respectively assume that history is driven by an inexorable directional force or by a strict cycle. Neither theory of history is supported by data on long-term trends in wars involving great powers or developed countries. In Better Angels I summarized these data (from Jack Levy, Lewis Richardson, Peter Brecke, and others) as a superposition of four patterns (p. 192): (1) No cycles; (2) A big dose of randomness; (3) A long-term escalation in the destructiveness of war, which made a substantial U-turn after 1945; and (4) Long-term declines in the frequency and duration

of war. Multiplying the trends in (3) and (4) yields the overall

decline in war that we call The Long Peace, and Factor (2) should keep us humble and cautious. But nothing supports the systematic pessimism of the fables about plummeting men or complacent turkeys.

Nor do the cautionary tales about pre-World-War I optimism tell us much, except that we should always be cautious. First, the infamous Norman Angell did not predict that war was impossible, only that

it was economically irrational. He feared that ideology and fear might lead the leaders of great powers to blunder into a disastrous war, and he was right. Second, though the world of a century ago had seen unprecedented levels of trade and economic integration, Bruce Russett and John Oneal have shown that when they are measured quantitatively (as a proportion of GDP) they are a tiny fraction of the levels the world has seen since 1945 (Better Angels, p. 286). Russett and Oneal’s two other statistical predictors of peace (democracy and membership in intergovernmental organizations) are also far

higher today, and other indicators of war-readiness such as the prevalence and length of conscription, the proportion of the population in uniform, overall prosperity, and the political participation of women are also more favorable today. In the realm of ideas, romantic militarism and nationalism have ceded ground to war aversion and liberal humanism, and of course nowadays we have knowledge of two destructive world wars and an awareness of the possibility of a nuclear catastrophe. In no other realm of human experience could one credibly say that we have learned nothing in the past century and that the assessments of today are no more trustworthy than those of a hundred years ago.

There is, of course, a tragic-poetic vision of the human condition in which we are condemned to repeat history, to be felled by our own hubris, to regress to our nature red in tooth and claw, and so on, but it is not grounded in historical or biological fact. If The Long Peace endures, it would not be the first time in history that a longstanding barbaric institution has been abolished or at least decimated. Wars involving great powers and developed states could very well join human sacrifice, chattel slavery, public torture-executions, auto-da-fés, debtors’ prisons, bear-baiting, foot-binding, gentlemanly dueling, witch hunts, and trephination on the ash heap of history.

Nor does a realistic, nonromantic view of human nature require perpetual war (and I can speak with some authority on this, having championed a thoroughly unsentimental understanding of the crooked timber of humanity in How the Mind Works and The Blank Slate). Though Homo sapiens undoubtedly evolved with violent instincts, those instincts are triggered by particular circumstances; they are not a hydraulic urge that must periodically be discharged. And though we evolved motives that can erupt in violence, we also evolved motives that can inhibit violence, including self-control, empathy, a sense of fairness, and open-ended cognitive mechanisms that can devise technologies for reducing violence.

None of this is to

say that

The Long Peace must endure. On top of the many systematic trends that militate against the resumption of great-power and developed-state war, there are the black

swans, long tails, and unknown unknowns that could poke big spikes up into the declining gradient. Perhaps there is some charismatic politician working his

way up through the Chinese nomenklatura who dreams of rectifying the intolerable insult of Taiwan once and for all, provoking an American or international response. Perhaps an aging Putin will seek historical immortality and restore Russian greatness by swallowing a former Soviet republic or two. Perhaps terrorists from some liberation movement no one has heard of are plotting an attack of unprecedented destruction, or a utopian ideology is fermenting in the mind of a cunning fanatic somewhere who will take over a major country and try to impose it everywhere.

Certainly no one could rule out these low-probability/high-impact events, or even begin to estimate their cumulative probability. But acknowledging our ignorance about improbable, trend-defying events is different from denying the existence of the trends. It seems to me that the Long Peace is a genuine trend that clusters

with other, more-often-than not, more-or-less successful attempts over the course of human history to contain our violent impulses.

***

Steven Pinker is Harvard College Professor of Psychology at Harvard University and the author of The Better Angels of Our Nature: Why Violence Has Declined.

The Long Peace is not an “it,” produced by a single monolithic cause or set of causes, but is instead

a “they” of different, coincident factors. Perpetuating such a peace in its current complex form will indeed prove daunting. However, this does not mean that the world need descend again into darkness and carnage. We can benefit from elements of the

Long Peace. The task is to identify which elements of the peace perpetuate where, and why.

The Long Peace can be parsed into at least four distinct empirical relationships:

1.) The hierarchical organization of the most powerful nations in the period into two competing ideological blocs anticipated, but failed to produce, major war.

2.) Developed democracies have been much less likely to fight each other.

3.) Developed democracies have not proven less willing/able to fight non-democracies.

4.) Every other combination of states behaved more-or-less like they always have.

Let’s take on the first relationship here, since arguably it is the most important. The peace among democracies would scarcely have been noticed if major war had broken out among the East and West in that past 60 years. At the same time, war between developing states is either nothing new or the product of what used to be called neo-imperialism and is now more fashionably described as policing the global commons. The fact that powerful nations attack the weak, but that weak nations seldom initiate such contests is hardly remarkable. The manner in which developed/powerful states deter or coerce conflict in

the developing world is a subject worthy of attention, but is something that must be addressed elsewhere.

The key feature of the Long Peace is really that the Cold War never got hot. Most scholars point to structural (bipolarity) or strategic (nuclear deterrence) factors to explain Cold War stability. The structural conditions of the Cold War are unlikely to repeat themselves in the coming decades, implying that Cold War stability should not persist. This was pointed

out by realists in the 1990s (Mearsheimer, Waltz). Yet, the Long Peace of the Cold War period has persisted for twenty years, implying that structural/strategic factors are not necessary for stability. Lieber and Press in The Rise of U.S. Nuclear Primacy suggest that the United States could today conduct a successful first strike against Russia, China, or both. If Cold War opponents were held in check by MAD, or bipolarity, then nuclear primacy/hegemony should imply the opposite. We

observe that the Long Peace persists regardless of primacy.

A different explanation for Cold War stability lies in the ideological nature of the struggle. Stability results when no nation perceives a benefit from acting aggressively. Nations could be inhibited by war risks (bipolarity), or costs (nuclear deterrence), but these theories tend to run into logical problems stemming from the zero-sum nature of conflict, and from the ability of actors to forge bargains preempting fighting; if cost inhibits me, it encourages my enemies, and so on. It is much easier to account for a lack of aggression by arguing that neither side sees a sufficient benefit in the outcomes likely to result from war. The United States and Canada neither deter nor balance one another.

They just lack reasons to fight, perhaps because neither covets the other’s territory and each prefers an organization and disposition of international politics that looks similar enough to what the other prefers.

In contrast to the actions of previous world powers, the United States in particular has not

been much interested

in accumulating additional territory. Instead, it desires to influence the politics of other nations, and the conditions under which nations interact and decisions are made in world affairs. This shift in emphasis from competition over land and tangible goods to attempts to influence made it possible for the United States to adopt containment (e.g., Kennan’s long telegram). For its part, the Soviet Union — after an initial conquests to create buffer states — was able to substitute the export of domestic revolution for direct confrontation with the West. The fact that the conflict was over states of affairs rather than stuff meant that both sides were able to, in effect, wait out the collapse of the other.

The United States and the Soviet Union clearly envisioned very different world orders. This could have led to war. Yet, it was unclear how a general war would bring about conditions either side preferred. It is much more difficult to change the preferences of people and societies than to simply occupy land, as both sides discovered in various fruitless and expensive “proxy wars.” Given the intractability of each side’s goals to a military solution, both were willing to wait-and-see. Ironically, the Soviet Union’s initial attempt to pursue security through territory meant that it faced economic burdens that hastened its downfall.

It seems unlikely today that any nation will adopt a grand strategy similar to that of the Soviet Union, or indeed pursue

territorial aggrandizement, as is so common in history. If for example China adopts aggressive territorial objectives, it will no doubt prove counter-productive just as it did for the Soviet Union. This seems to have been one of the insights

of Deng Xiaoping, who recognized that China’s future lay in commerce rather than conquest. It is very possible that growing Chinese prosperity will both reduce the basis for territorial conflict between China and the West, and increase mutual interests. Even if differences remain, both sides may well conclude that there is little point in acting them out through military force. The insignificance of territory as a basis for war in the modern world, and the different nature of policy conflict, sometimes more intense but also the opposite, is a major change in world affairs, something that is worth pursuing as its own blog segment.

***

Erik Gartzke is an associate professor of political science at UC

San Diego. Gartzke’s primary area of study involves the impact of information and institutions on war and peace. He applies bargaining theory, rational choice institutional theory, concepts of power and social identity, and statistical analysis to four substantive areas of interest: 1) The liberal peace, 2) international institutions, 3) diplomacy, and 4) the system overall.

by Erik Gartzke

The Long Peace is not an “it,” produced by a single monolithic cause or set of causes, but is instead a “they” of different, coincident factors. Perpetuating such a peace in its current complex form will indeed prove daunting. However, this does not mean that the world need descend again into darkness and carnage. We can benefit from elements of the Long Peace. The task is to identify which elements of the peace perpetuate where, and why.

The Long Peace can be parsed into at least four distinct empirical relationships:

1.) The hierarchical organization of the most powerful nations in the period into two competing ideological blocs anticipated, but failed to produce, major war.

2.) Developed democracies have been much less likely to fight each other.

3.) Developed democracies have not proven less willing/able to fight non-democracies.

4.) Every other combination of states behaved more-or-less like they always have.

Let’s take on the first relationship here, since arguably it is the most important. The peace among democracies would scarcely have been noticed if major war had broken out among the East and West in that past 60 years.

At the same time, war between developing states is either nothing new or the product of what used to be called neo-imperialism and is now more fashionably described as policing the global commons. The fact that powerful nations attack the weak, but that weak nations seldom initiate such contests is hardly remarkable. The manner in which developed/powerful states deter or coerce conflict in the developing world is a subject worthy of attention, but is something that must be addressed elsewhere.

The key feature of the Long Peace is really that the Cold War

never got hot. Most scholars point to structural (bipolarity) or strategic (nuclear deterrence) factors to explain Cold War stability. The structural conditions of the Cold War are unlikely to repeat themselves in the coming decades, implying that Cold War stability should not persist. This was pointed out by realists in the 1990s (Mearsheimer, Waltz). Yet, the Long Peace of the Cold War period has persisted for

twenty years, implying that structural/strategic factors are not necessary for stability. Lieber and Press in The Rise of U.S. Nuclear Primacy suggest that the United States could today conduct a successful first strike against Russia, China, or both. If Cold War opponents were held in check by MAD, or bipolarity, then nuclear primacy/hegemony should imply the opposite. We observe that the Long Peace persists regardless of primacy.

A different explanation for Cold War stability lies in the ideological nature of the struggle. Stability results when no nation perceives a benefit from acting aggressively. Nations could be inhibited by war risks (bipolarity), or costs (nuclear deterrence), but these theories tend to run into logical problems stemming from the

zero-sum nature of conflict, and from the ability of actors to forge bargains preempting fighting; if cost inhibits me, it encourages my enemies, and so on. It is much easier to account for a lack of aggression by arguing that neither side sees a sufficient benefit in

the outcomes likely to result from

war. The United States and Canada neither deter nor balance one

another. They just lack reasons to fight, perhaps because neither covets the other’s territory and each prefers an organization and disposition of international politics that looks similar enough to what the other prefers.

In contrast to the actions of previous world powers, the United States in particular has not been much interested in accumulating additional territory. Instead, it desires to influence the politics of other nations, and the conditions under which nations interact and decisions are made in world affairs. This shift in emphasis from competition over land and tangible goods to attempts to influence made it possible for the

United States to adopt containment (e.g., Kennan’s long telegram). For its part, the Soviet Union — after an initial conquests to create buffer states — was able to substitute the export of domestic revolution for direct confrontation with the West. The fact that the conflict was over states of affairs rather than stuff meant that both sides were able to, in effect, wait out the collapse of the other.

The United States and the Soviet Union clearly envisioned very different world orders. This could have led to war. Yet, it was unclear how a general war would bring about conditions either side preferred. It is much more difficult to change the preferences of people and societies than to simply occupy land, as both sides discovered in various fruitless and expensive “proxy wars.” Given the intractability of each side’s goals to a military solution, both were willing to wait-and-see. Ironically, the Soviet Union’s initial attempt to pursue security through territory meant that it faced economic burdens that hastened its downfall.

It seems unlikely today that any nation will adopt a grand strategy similar to that

of the Soviet Union, or indeed pursue territorial aggrandizement, as is so common in history. If for example China adopts aggressive territorial objectives, it will no doubt prove counter-productive just as it did for the Soviet Union. This seems to have been one of the insights of Deng Xiaoping, who recognized that China’s future lay in commerce rather than conquest. It is very

possible that growing Chinese prosperity will both reduce the basis for territorial conflict

between China and the West, and increase mutual interests. Even if differences remain, both sides may well conclude that there is little point in acting them out through military force. The insignificance of territory as a basis for war in the modern world, and the different nature of policy conflict, sometimes more intense but also the opposite, is a major change in world affairs, something that is worth pursuing as its own blog segment.

***

Erik Gartzke is an associate professor of political science at UC San Diego. Gartzke’s primary area of study involves the impact of information and institutions on war and peace. He applies bargaining theory, rational choice institutional theory, concepts of power and social identity, and statistical analysis to four substantive areas of interest: 1) The liberal peace, 2) international institutions, 3) diplomacy, and 4) the system overall.

The decline of Great Power war thesis advanced by the NIC analysis pivots on an important empirical fact: there haven’t been any since World War II. The cause, or causes, of the “Long Peace” is less transparent and widely debated.

I advance two arguments here. First, U.S. power is the principal cause of stability in international politics but is likely to weaken in the timeframe considered by the NIC report. As the relative power of the U.S. declines, the likelihood of great power conflict rises. Second, the NIC study underplays the probability of intense security competition with China. As a consequence, I am doubtful the world has seen the end of great power war.

In addition to ensuring the security of the U.S. and its allies, American primacy provides four benefits for the world. The first has been a more peaceful world. During the Cold War, U.S. leadership reduced friction among many states that were frequent antagonists. Today, American primacy reduces nuclear proliferation incentives and helps keep a number of historically dicey relationships peaceful—such as between Greece and Turkey.

Second, American power gives the United

States the ability to

spread the positive norms and values the NIC document identifies.

Doing so is a source of much good for the countries concerned as well as the United States. This is because liberal democracies are more likely to align with the United States and be sympathetic to the American worldview.

Third, along with the growth in the number of democratic states around the world has been the growth of the global economy, as the NIC analysis recognizes. With its allies, the United States has toiled to create a globalized trade regime defined by free trade and commerce, respect for international property rights, mobility of capital and labor markets. The prosperity that flows from this liberal order is a global good.

Fourth, the United States has been willing to use its power not only to advance its interests but also to promote the welfare of people all over the globe. The U.S. military has participated in scores of humanitarian operations since the end of the Cold War. Given these great benefits, we may be confident of one prediction: Many people around the world will miss U.S. primacy when it’s gone.

Without U.S.

power, the liberal order is likely to end, and this alone is

liable to exacerbate tensions. But the waning of U.S. power, at least in relative terms, introduces

additional problems concerning the future prospects for great power war. Declining hegemons have a choice. They may labor to reverse their decline, perhaps through innovation or greater competition with the challenger, which may lead to conflict. Or they may accept it, and watch their influence wither and allies drift away, which also introduces avenues of conflict. There is no reason to believe that the United States will escape this difficult decision, either of which holds the prospect of conflict with China.

On the other side of the coin, China’s rise in relative power contains great risks of conflict and intense security competition.

Briefly, here are three major reasons for pessimism when we consider the likelihood of a Sino-American conflict. First, China has numerous border disputes in the South and East China Seas, India, and, of course, Taiwan. Each of these conflicts is dangerous, particularly those in the South China Sea, due to the national security interest of Beijing, Washington and its allies, and the risk of intentional or inadvertent escalation.

Second, we must consider Beijing’s and Washington’s conflicting grand strategic interests. The report underplays how belligerent, revisionist, and risk accepting China may be in the future. The world has witnessed China’s abandonment of Deng’s 24-Character Strategy and talk of a “Peaceful Rise” in favor of rapid military expansion and what can only be described as a strategic autism or tone deafness that has alarmed Japan, India, and the ASEAN states, to the benefit of the U.S. Unfortunately, unless Beijing’s trajectory changes, it is on a collision course with Washington.

Third, the systemic problems of alliances, mutual concerns over credibility, buck-passing, “chain ganging” and abandonment, confront the United States in its explicit or de facto alliances with Japan, India, the Philippines, and Vietnam. These alliances provide prodigious benefits but also introduce pathways to conflict with China. Friends are great to have but they can get you into trouble. To this, we must add the dangers well identified by theories of hegemonic war and power transition concerning the incentives, held by the declining hegemon or challenger, or both, for arms racing and other forms of intense security competition.

In sum, there are significant reasons to doubt the decline of Great Power war thesis in the context of China’s relations with other Great Powers.

***

Bradley A. Thayer is a Professor of Political Science at Baylor University and

Consultant to DoD.