SYNOPSIS

Should America encourage nuclear proliferation by its friends and allies in Asia? A shifting military balance and uncertainty about US commitments are intensifying the debate. This piece explores why allied proliferation might be a good thing – but is probably still a dangerous, destabilising idea.

COMMENTARY

Should the United States encourage its friends in Asia to develop nuclear weapons? There is a view in the region that Asia may be approaching a new age of nuclear proliferation. In this commentary, I examine why a more proliferated Asia might be a good thing – but would probably turn out badly in the end.

For decades, the United States has sought to constrain proliferation in Asia and globally. To do so, Washington has provided security guarantees (or quasi-guarantees) to vulnerable allies and partners, while also using coercive pressure and threats of abandonment to dissuade friendly countries, like Japan and South Korea, from seeking nuclear weapons.

By any reasonable standard, that project has succeeded. After China’s first nuclear test in 1964, it seemed that many Asian countries might go nuclear. But more than six decades later, only India, Pakistan, and North Korea have followed Beijing down that path.

Today, however, four issues are compelling a rethink of the Asian non-proliferation order.

First, the conventional military balance is shifting. It is now far from assured that America could defeat a Chinese blockade or invasion of Taiwan. If America can’t protect front-line states, they may look for other ways of protecting themselves.

Second, the nuclear balance is shifting. For decades, America has backstopped its conventional forces with the threat of nuclear escalation in a crisis. But as North Korea develops capabilities that can hit the US homeland, and China races to become a nuclear peer, America’s escalation options become less attractive – and extended nuclear deterrence comes under greater doubt.

Third, the Ukraine precedent is troubling. A nuclear-armed country committed aggression against a weaker neighbour, while using the threat of nuclear war to deter the United States from intervening directly. South Korea, Japan, and Taiwan all worry that their nuclear-armed enemies might try something similar.

Fourth, America is becoming an ambivalent protector. There are rumours that the forthcoming National Defense Strategy will focus more on the Western Hemisphere than the Western Pacific. President Donald Trump often says America should not bear primary responsibility for defending countries an ocean away. Perhaps a new era of self-help is here.

It’s not shocking, then, that there are stirrings of proliferation in South Korea and even Tokyo these days. President Trump has periodically indicated his openness to that prospect since his first run for the White House. So, what would be the advantages and risks?

The most obvious advantage might be to shore up a deteriorating status quo in a contested region. Managed proliferation might give friendly countries better guarantees of their own territorial integrity, while reducing military burdens on Washington. At best, it might create a nuclear peace in East Asia, of the sort that prevailed (tenuously) in Europe during the Cold War.

A second advantage would be to swap direct deterrence for extended deterrence. Extended deterrence has always been challenging because it requires a great power to risk destruction over territory that is not its own. Direct deterrence is thought to be more credible because it requires the nuclear possessor to be willing to risk escalation only when its own survival is at stake.

Third, managed proliferation might bring a better balance within the democratic world. A longstanding critique is that America still treats allies as protectorates, rather than as equal partners in their own defence. A world in which Japan, South Korea, Taiwan, and Australia possess nuclear weapons would diffuse responsibility among leading democracies. It might better reflect the realities of a world that has shifted dramatically since those alliances and partnerships were formed decades ago.

For these reasons, managed proliferation might make the best of a worsening situation. But there are many reasons to worry that it could just make a mess.

First, there is the transition problem. Countries that are threatened by a Japanese, South Korean, or Taiwanese bomb won’t just wait for them to cross the nuclear finish line – they may preempt those programmes militarily. Taiwan, which most needs nuclear weapons, will never get them without inviting a devastating Chinese strike. An effort to bring about managed proliferation might cause the very war that the strategy is meant to avoid.

Second, even if new entrants cross the nuclear finish line, small arsenals are vulnerable and create temptations for preemption in a crisis. In a showdown over the Senkaku/Diaoyu Islands in the East China Sea, China might try to eliminate a modest Japanese nuclear arsenal. That threat, in turn, incentivises hair-trigger launch postures that intensify instability. The fact that the geography of Northeast Asia is relatively compact and missile flight times are relatively short could have the same effect.

Third, nuclear arsenals may not do much good in the grey zone. NATO’s nuclear guarantees haven’t deterred Russian hybrid warfare against Europe. Likewise, there’s no guarantee a Taiwanese arsenal would prevent China from harassing outlying islands. Nuclear use has to be credible, and it’s doubtful that vulnerable countries would use nuclear weapons against a better-armed adversary in anything less than an existential crisis.

Fourth, proliferation may not stay limited. In an ideal scenario, only a few responsible democracies would acquire nuclear weapons. But what if the dominoes don’t stop there? Why wouldn’t Indonesia or Vietnam eventually want nuclear weapons? Once East Asia becomes a proliferation hotspot, perhaps other regions, like the Persian Gulf, might follow.

Fifth, more nuclear states mean more nuclear crises, with little guarantee that America can remain aloof. In a nuclear-armed Asia, every crisis between Japan and China, China and Taiwan, South and North Korea, or even South Korea and Japan will take on – explicitly or implicitly – a nuclear dynamic. And a nuclear conflict would have global implications, even if the United States was not originally involved.

Finally, even a nuclear-armed Asian country may still need US support. One reason the French arsenal could be kept relatively small in the Cold War was that Paris had Washington standing behind it to manage escalation at higher rungs of the ladder. Unless Japan (for example) develops an arsenal that matches China’s, it will remain outgunned at the top of that ladder, and may hesitate to initiate a nuclear exchange without US support. From a US perspective, then, a nuclearised Asia could still bring heavy responsibilities – with even greater dangers.

To sum up, managed proliferation is no silver bullet – it offers some conceptual attractions, but also some very dangerous flaws. There are no shortcuts to security and prosperity in a contested region. But the fact that the Asian military balance and confidence in American commitments are both eroding ensures that questions about a more proliferated region will continue to be asked.

About the Author

Hal Brands is the Henry Kissinger Distinguished Professor of Global Affairs at Johns Hopkins SAIS, a senior fellow at the American Enterprise Institute, and a columnist for Bloomberg Opinion. He was recently the S. Rajaratnam Professor of Strategic Studies at the S. Rajaratnam School of International Studies (RSIS) at Nanyang Technological University. His most recent book is The Eurasian Century: Hot Wars, Cold Wars, and the Making of the Modern World.