Even the gloomiest observers of Sino-US relations did not see a spat over a “spy balloon” looming over the horizon.

President Joe Biden’s decision to shoot down the Chinese balloon this weekend was in retrospect inevitable. Mr Biden faced extraordinary domestic political pressure to act, while the United States needed to protect the principle of territorial integrity. It would also have been near-impossible for Secretary of State Antony Blinken to continue with his planned visit to Beijing this week, with a media storm brewing at home.