When Xi Jinping tipped up at the White House recently Barack Obama made a proposal. The president said they both had an interest in setting up a serious dialogue between the US and Chinese armed forces. Mr Xi, who expects to be China’s president by this time next year, did not take long to think about the idea. His response was blunt: No.

Mr Xi’s trip to the US was publicly uneventful. The heir presumptive to Hu Jintao was careful to say nothing remarkable. His hosts, particularly vice-president Joe Biden, used the occasion to make some acerbic remarks about China’s approach to trade, intellectual property rights and such like. This is a US election year. All in all, though, there was no sign either of a meeting of minds or of a serious rupture.

The impression taken by US officials from the encounters was that once he is China’s president Mr Xi is likely to be tougher, more nationalist and closer to the military than Hu Jintao. This means that managing the most important relationship of the 21st century is unlikely to get any easier.