By Vipin Narang

The world is sliding toward a second nuclear age, one whose character will be dominated by regional nuclear powers with conflicting interests rather than by the United States or Russia. Regional nuclear powers such as India, Israel, Pakistan, North Korea, potentially Iran and others that might follow face different challenges in managing their nuclear forces than the superpowers. They have tighter resource constraints, often unstable domestic politics or even internal conflict, and hostile regional security environments. Some are forced to extract significant deterrent power from much smaller arsenals, which can strain command and control organs.

Some like India and China are content to rely on nuclear weapons to deter strictly nuclear use, and therefore have the luxury of adopting no first use clauses and relatively assertive command and control structures that privilege arsenal security. These nuclear powers have a nuclear strategy best described as “assured retaliation,” and they are able to select it because of advantageous geographic buffers and strong conventional forces that obviate the need to rely on nuclear weapons as warfighting tools.

Others, like Pakistan and perhaps several emerging nuclear states in the next two decades, are not so lucky. Nuclear states that face a conventionally superior adversary are often tempted to adopt more aggressive first use postures that threaten nuclear use in a conventional conflict—as NATO did during the Cold War. With sometimes unstable regimes and internal threats, regional powers that adopt such a posture risk not only the intentional use of nuclear weapons in a conflict, but nuclear accidents and more disturbingly of course, nuclear terrorism.

It is an open question as to what type of nuclear posture future regional nuclear powers such as Iran, and others that might follow, will adopt. There are reasons to think Iran might look more like India or China, trying to deter nuclear use and an existential threat to the regime’s existence. But there are also reasons to think, particularly given the structure of the Iranian Revolutionary Guards Corps, that Iran might go down the path of Pakistan and adopt a first use nuclear posture to deter even limited conventional threats from its adversaries. Keeping a close eye on not only which states pursue nuclear weapons, but also which nuclear postures they adopt, will be a critical determinant of stability or instability in the Middle East, South Asia, and East Asia.

What is certainly clear is that the emergence of a potential cascade of nuclear powers across Asia—from west to east—carries with it significant challenges that we have not yet faced. First, the number of potential nuclear powers that border each other, with historical territorial disputes and irredentist claims, is a novel challenge. The risk of armed conflict, checkerboard nuclear alliances (e.g., persistent rumors about Saudi-Pakistani nuclear connections), and catastrophic misperceptions are all heightened in such a multipolar nuclear landscape. Second, for the most part, the Cold War competition settled into a pattern where both the United States and the Soviet Union had an interest in largely preserving the status quo. Some new nuclear states across Asia may view nuclear weapons as an instrument to revise the status quo—that is for deterrence as well as offense or compellence, despite the historical difficulty of the latter. We have already seen some of the effects of this in South Asia, where Pakistan has more aggressively employed state-based terrorist organizations to attack metropolitan India, using its first use posture as a shield behind which it can act against its conventionally superior neighbor.

What role can the United States play as these dynamics unfold over the next two decades? Can a broader US extended deterrent to Middle East allies who might be tempted to proliferate stanch the cascade of proliferation? There are two reasons to think that this might be difficult. First, states such as, hypothetically, Saudi Arabia might prefer to have their own sovereign deterrent against a future nuclear Iran rather than outsourcing it to the United States. Second, the risk that a broader US extended deterrent might generate “reckless allies” that might drag the United States into conflicts would be a serious concern. Broader nonproliferation and counter-proliferation efforts might slow the emergence of this landscape, but it has historically been very difficult to stop determined states from acquiring nuclear capabilities.

Realistically, the best hope the United States probably has in managing this emerging nuclear landscape is to stay engaged across Asia to help ensure that small disputes do not escalate to armed conflict between nuclear powers. It may also be time to revisit export control laws that prohibit the sharing of negative control technologies and best practices that might help secure the arsenals of new nuclear states. In the new landscape, with nuclear weapons dispersed across unstable states, a premium ought to be put on ensuring that those weapons are as secure as possible.

Vipin Narang is Assistant Professor of Political Science at the Massachusetts Institute of Technology, and a member of its Security Studies Program.