USA vs China: What a Nuclear War Would Look Like

China is the only nuclear power expanding its arsenal fast enough to reach parity with the United States. A US–China exchange is not the Cold War rerun of Russia–USA — it’s a Pacific war, fought across alliance lines that run through Japan, South Korea, and Taiwan. The model shows an exchange that escalates hard but, more often than the Russia case, stops short of the end of the world.

Great powers trade strategic strikes. Millions die in the opening hours and radioactive fallout crosses continents. Humanity survives, but the prewar world does not.

Simulated outcome

Each run starts the same way — United States launches a first strike on China — and then the escalation engine plays the alliance cascade forward, decision by decision. Because retaliation, alliance loyalty and doctrine are probabilistic, the 500 runs don’t all end the same way:

Estimated human cost: 13.1 million+ in direct strikes, with billions more at risk from the ensuing nuclear winter.

Modeling note: these pages show the engine’s projected escalation, assuming launched weapons reach their targets. The live 3D simulation additionally rolls probabilistic missile-defense interception, so an individual run there may be less severe. Casualty figures are first-order estimates from capital-population and arsenal data — a floor, not a ceiling.

Arsenal face-off

What each side brings to the exchange, from the simulator’s arsenal data (SIPRI/FAS-derived estimates):

The alliance cascade

A strike is never just between two countries. These are the nations the model most reliably pulls into the United States–China war (share of runs in which each is drawn in):

Alliance clauses triggered

The closest we’ve come

Related scenarios