The US failure makes it much harder for Biden to push his core message that “America is back”. By contrast, it fits perfectly with two key messages pushed by the Chinese (and Russian) governments. First, that US power is in decline. Second, that American security guarantees cannot be relied upon.

If the US will not commit to a fight against the Taliban, there will be a question mark over whether America would really be willing to go to war with China or Russia. Yet America’s global network of alliances is based on the idea that, in the last resort, US troops would indeed be deployed to defend their allies in Asia, Europe and elsewhere.

China is already the dominant economic power in east Asia. But most Asian democracies look to the US as their main security partner. So it is very helpful to Beijing if Washington’s credibility is undermined. Of course, the situations and stakes in Taiwan or the South China Sea are different from those in Afghanistan. But events there will still resonate around the world.