The US hasn’t just left Ukraine vulnerable; it is also provoking Xi’s intensifying attitude towards what he considers a renegade province

Sheer ignorance, fed by malign intent, historical prejudice and mutual misunderstanding, is often the crucial spark that ignites simmering international conflicts. If Adolf Hitler, remarkably ignorant of the US, had grasped the true extent of American industrial might, would he still have fatefully declared war on Washington in 1941?

When the Soviet Union invaded Afghanistan in 1979, it evidently had no idea what it was getting into. Humiliating defeat contributed greatly to its subsequent disintegration. In 1990, Iraq’s Saddam Hussein attacked Kuwait, convinced he had a green light from the White House. In all these cases, stupidity produced disastrous misjudgments that proved fatal.

Simon Tisdall is a Guardian foreign affairs commentator