A nuclear arms race isn’t new, per se, but it does help refocus our attention on dangers that have long been with us

This week, the U.S. Department of Defence released its annual report on China’s military power. As usual, the report covers a comprehensive range of technological, tactical, and strategic assessments of Beijing’s goals and capabilities. But it comes at a time when tensions are rising – and even more frighteningly, nuclear weapons are emerging from the background to be a prime issue in the strategic competition between the two powers.

There is both more and less here than some of the breathless commentary might suggest. China has long been a slightly odd outlier among nuclear weapons states: Despite its near-superpower status, its arsenal has remained closer in size to those of middle powers like France, Britain, or India than to the United States’ or Russia’s. Until recently, China also seemed content with a much less diversified set of delivery systems, relying heavily on land-based intercontinental ballistic missiles and a very limited fleet of missile submarines, compared to the full-fledged “triads” of bombers, submarines, and ICBMs fielded by Moscow and Washington.

That seems to have changed. Last fall, the People’s Liberation Army Air Force showed off a new variant of their H-6 bomber carrying what seems to be an air-launched ballistic missile, a type of weapon that makes the most sense with a nuclear warhead. The PLA Navy has been developing new submarine-launched missiles and building more submarines to carry them. Nor has the land-based leg of the triad been left out: China has been building new silo fields for ICBMs and recently tested a hypersonic boost-glide missile with a fractional orbital bombardment capability. Of course, new delivery systems do not mean much if they do not have warheads, and on that front, the new DoD report suggests that the PLA will increase its deployed warhead numbers from roughly 350 to perhaps a thousand by 2030.

But these developments are not happening in a vacuum. Even the mooted increase in Chinese warhead numbers will still not bring it to parity with the United States, which fields nearly 4,000 (though per the terms of the New START arms-limitation treaty, less than half of those are available for immediate use). Meanwhile, the United States has been significantly modernizing its own nuclear delivery systems, including stealth strike fighters and bombers, new ballistic missile submarines and new ICBMs. The U.S. has also pulled out of several key arms control treaties in recent years, though it is worth noting that those treaties were originally signed between the U.S. and USSR, and China was never party to them. And finally, the United States has been actively developing missile defences, which in theory could undercut the logic of nuclear deterrence.

And yet, for all these technological developments, the underlying logic of nuclear threat remains much the same as it has been. A new nuclear arms race isn’t new, per se, but it does help refocus our attention on dangers that have long been with us.

Take, for example, the hypersonic missile test that garnered so much attention. Certainly, the ability to dodge missile defences and attack from angles not covered by early-warning radars offers some advantages in certain apocalyptic scenarios – but the underlying reality is that China has long since had the ability to deliver high-yield nuclear weapons to targets in the continental United States; the U.S. has the ability to do the same to China, and there is virtually nothing that either can do to prevent it. Non-silo-based missiles – whether mounted on submarines or ground vehicles – are incredibly difficult to destroy en masse before they can be launched, and once the missiles are flying, interception is nearly impossible. The U.S. missile defence system, for all the billions lavished on it, has not been reliable in real-world testing and can be easily overwhelmed by sheer numbers (or by relatively cheap and simple decoy warheads).

As experts in the field have observed, the purpose of China’s sudden nuclear acceleration might well not be to win, or even to fight, a nuclear war. The point is to establish and maintain a credible deterrent – a front-of-mind presence in adversarial decision-making circles, if you will – in order to open the space for more aggressive moves at the conventional or unconventional non-nuclear level. (Russia’s recent push for highly unconventional systems like the Poseidon super-torpedo and a nuclear-powered cruise missile are harder to explain on these lines, since Moscow already has a massive and deeply survivable nuclear arsenal.)

To be clear, none of this is good news. Regardless of how much policy attention is paid to them, the very existence of nuclear weapons creates an inherent possibility of nuclear war, through accident, misunderstanding, miscalculation, or – most likely – a combination of all three. Adding new systems, especially those with seemingly game-changing capabilities, changes the balance of deterrence, which is already a fragile thing, held as it is between untrusting and frequently uncomprehending adversaries. It is not at all clear what tactical advantage is worth that level of risk.