Reluctantly, America eyes building more nuclear weapons
The nuclear de-escalation that followed the cold war is over, the Pentagon warned this month. In its place is a new rivalry among nuclear and almost-nuclear powers, some of them paranoid. It is more complex and less predictable than the old, bipolar contest between America and the Soviet Union. That makes it more dangerous.
Facing new nuclear threats will be a test for America, even as its resources are strained and its politics have grown more isolationist. It must reassure allies that its nuclear umbrella still protects them. And, unfortunately, it will have to expand its nuclear arsenal. Falter on either count and this will fuel proliferation among enemies and friends alike, making America and the world less secure.
Evidence of new dangers is everywhere. China is building hundreds of missile silos in its northern deserts. Vladimir Putin blusters about using nuclear weapons and threatens to aim more Russian missiles at Europe. Even as it is poised to launch another conventional attack on Israel, Iran is closer to a bomb than it was five years ago, having reportedly recently made advances in weaponisation, the process of turning enriched uranium into warheads. North Korea says it is “bolstering” its nuclear programme. This week Donald Trump claimed he would build an “Iron Dome” missile shield to protect America. “It just takes one maniac,” he explained.
All this is a big shift. Between 1986 and 2023 the number of warheads worldwide fell from 70,000 to 12,000 as the end of the cold war ushered in defence cuts and arms control. America slimmed its arsenal while keeping a powerful deterrent. Today it has a smaller “triad” of nuclear weapons that could be launched from land, air or under the sea. Many of its warheads are aimed at its adversaries’ warheads. And it offers “extended deterrence”: a promise to defend allies if required. As recently as 2009 Barack Obama still hoped for “a world without nuclear weapons”. When he became president, Joe Biden aspired to re-energise arms control after the chaos of the Trump administration.
Instead, nuclear threats have proliferated and mutated. The number of warheads is rising again, as China’s arsenal expands from a few hundred a decade ago to perhaps 1,000 by 2035. This will create a third nuclear superpower for the first time. Meanwhile, technology is spreading into new domains and hands. Russia plans to put a bomb in space; North Korean warheads can reach the continental United States. Militias such as those of the Houthis have sophisticated missiles (albeit conventionally armed). China, Iran, Russia and North Korea are co-operating on military matters and could collude on missile technology, too.
The Pentagon fears all this will stretch America’s arsenal thin—will it have enough warheads to deter China, Russia and North Korea at the same time?—and further complicate the psychology of brinkmanship. It also makes extended deterrence more difficult. When America first brought South Korea under its nuclear umbrella, for example, North Korea had no nukes and no long-range missiles. Now it has nuclear missiles that could incinerate American cities. The hope that Iron Dome shields, of the kind used in Israel and Ukraine, can protect America is misplaced: they work less well against long-range missiles. For any American president, the question looms: would you sacrifice Los Angeles to avenge Seoul? And do your enemies believe you would?
Allies face tough questions, too. They know isolationist populism isn’t going away in America, regardless of who occupies the Oval Office next year. They understand that America’s forces are stretched and its promise of extended deterrence is less credible than it was. If South Korea doubts America’s umbrella, it might build its own bomb—and 70% of South Koreans think it should. Japan might follow a similar logic. Europe is discussing whether British and French nuclear weapons are enough to deter Russia if America abandons nato. If Iran gets the bomb, so might Saudi Arabia. Proliferation would be destabilising. With more fingers on more red buttons, the chance of miscalculation increases. The odds of conventional war may rise, too, if countries try to stop their enemies from crossing the nuclear threshold.
How should America respond? Arms-control talks have stalled. Russia has suspended its participation in New START, a pact which expires in 2026. China, never much interested in nuclear-risk reduction talks with America, halted them in July. North Korea has spurned offers to talk; Iran is mercurial. It would be unwise to give up on arms control. But if these foes return to the table, they are more likely to negotiate seriously if they know America is in a strong position.
That means America should be prepared to build a larger and more diverse arsenal, once New START expires. Mr Biden’s Pentagon has already begun the pivot, embracing new weapons such as a sea-launched nuclear-armed cruise missile. It is exploring how to “upload” warheads quickly to existing launchers, should Russia and China sprint ahead. A President Trump would probably continue the build-up.
Mutually assured disruption
But a lack of bipartisan agreement over extended deterrence creates uncertainty. Mr Biden has rightly sought to reassure allies by sending more nuclear-capable bombers and submarines to Europe and Asia, and by consulting them more closely, so they understand how weapons might be used and feel confident that America’s promises are not idle.
Mr Trump and some isolationist Republicans may argue that none of this is necessary to protect America. They are wrong. Extended deterrence is both essential and in its narrow self-interest. Counterintuitively, America chooses to make its homeland more vulnerable in order to protect allies thousands of miles away. In so doing, it helps avert destabilising nuclear proliferation. This logic has kept America, and perhaps even its adversaries, safer for 80 years. In a dangerous world, it would be reckless to let America’s nuclear umbrella fray.■
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