Why the US is now facing a two-front nuclear arms race

US President Donald Trump.

The new nuclear race is no longer a bipolar contest like the Cold War. The United States now has to deter two major nuclear rivals at once, even as its own modernization plans were designed for a world in which Russia was the only peer competitor and China had a minimal force. Beijing is rapidly building toward rough parity in deployed warheads by the mid-2030s, while Moscow is using nuclear threats and exotic weapons projects to offset its conventional weaknesses in Ukraine, the Wall Street Journal reported.

China’s sprint to a “true” nuclear triad

For decades, China kept a relatively modest nuclear arsenal, relying on a doctrine of minimum deterrence. That logic has changed. US intelligence now expects Beijing to field a full triad of land-, sea- and air-launched nuclear systems, with enough deployed warheads to be in the same ballpark as the US by the mid-2030s.

Xi Jinping showcased this new capability in September at a military parade in Beijing, displaying road-mobile intercontinental ballistic missiles and the outlines of a maturing triad. The political message was as important as the hardware: Xi sat flanked by Vladimir Putin and Kim Jong Un, signalling a looser but visible alignment among three nuclear-armed states that are all adversarial to Washington.

Moscow’s nuclear brinkmanship and “wonder weapons”

Russia still has the world’s largest nuclear stockpile and has used that leverage aggressively since invading Ukraine in 2022. Vladimir Putin has repeatedly hinted at nuclear use to limit Western support for Kyiv, moved nuclear weapons into Belarus, and publicized tests of systems such as the Burevestnik nuclear-powered cruise missile and the Poseidon underwater drone.

Many Western experts see these projects as more psychological than practical, costly ways to create fear and uncertainty rather than transform the military balance. But the signalling works: every time Russia rattles its nuclear sabre, it forces Washington and NATO to weigh escalation risks before sending more advanced weapons to Ukraine.

Why US planners are worried

American nuclear forces are being modernized, but the entire plan was sized for a different era: further bilateral cuts with Russia and no serious challenge from China or North Korea. That assumption has collapsed. Washington must now think about extreme scenarios in which a war in Europe overlaps with a crisis over Taiwan and a potential North Korean move on South Korea.

In such a multi-theater conflict, US forces and stockpiles could be stretched thin. A bipartisan commission has already recommended that Washington consider expanding its arsenal for the first time in decades, to ensure it can deter Russia and China simultaneously. Former officials warn that the current posture was not built for this “two-peer” world.

Testing, deterrence and the risk of escalation

The debate is now shifting to nuclear testing. The US has not carried out a full-yield underground test since 1992, relying instead on subcritical experiments and simulations to keep its stockpile

reliable. Intelligence reports that Russia and China may be conducting more advanced underground tests have added pressure in Washington.

Trump has floated the idea of resuming US nuclear tests, arguing that Putin’s threats cannot go unanswered. Yet restarting explosive tests would carry diplomatic and environmental costs and could trigger a cascade of testing by other powers, undermining arms-control norms without necessarily improving deterrence.

A more crowded, less stable nuclear age

During the Cold War, deterrence theory rested on a grim kind of simplicity: two superpowers, each capable of destroying the other. Today, the US faces a world with three major nuclear powers, a more capable North Korea, and fraying arms-control regimes. China is not yet interested in binding limits while it is still building up, and the last remaining US-Russian treaty is running out of road.

The result is what strategists are calling a “third nuclear age”: more players, more weapons, more overlapping regional conflicts and a higher risk of miscalculation. The core question for Washington and its allies is whether they can adapt deterrence and arms control to a world where nuclear danger no longer runs along a single line from Washington to Moscow, but through Moscow, Beijing and Pyongyang all at once.