The Biden team believe that China is determined to displace the US as the world’s pre-eminent economic and military power, and they are determined to push back. They understand that much of the struggle will be about trade and technology. But they also know that a successful Chinese invasion of Taiwan would signal the end of US dominance of the Indo-Pacific.

Would the US go to war to prevent that happening? The short answer is that no one really knows. Not the military planners in Washington and Beijing, whose job it is to draw up elaborate plans for conflict over Taiwan. Nor, possibly, even America’s commander-in-chief, Joe Biden. So much would depend on the nature of the attack — and the domestic and international political situation at the time.

As the Cuba missile crisis of 1962 and the 1914 July crisis in Europe both demonstrated, world-shaking decisions about war and peace, are often made in a surprisingly haphazard fashion under the pressure of fast-changing events.

Maintaining a state of uncertainty is, in fact, a deliberate US policy — known as “strategic ambiguity”. The idea is to deter China from attacking Taiwan by suggesting that the US would defend the island, without issuing an explicit security guarantee that might, in itself, trigger a military showdown. Strategic ambiguity has helped America maintain the status quo over Taiwan for two generations.