In 1999 various NATO powers bombed Belgrade and thus compelled Serbia to quit its Kosovan province to the delight of the KLA ‘terrorist’ group. Carried out without the approval of the UN Security Council, it marked a high-water mark in humanitarian interventionism. And it led some practitioners and many academics to conclude that the norms of the Westphalian system for conducting relations among sovereign states were under challenge as never before. But in this booklet it is argued that Westphalian norms are now back in fashion, as the enthusiasm for uninvited humanitarian intervention, with its echoes of ‘high-minded imperialism’, symbolised by Tony Blair’s famous Chicago speech, no longer finds much favour - particularly so in the White House, where Barack Obama looks set on steering a markedly traditional, cautious and even conservative course.