Ever since 1945, the US has regarded itself as the leader of the “free world”. But the Obama administration is facing an unexpected and unwelcome development in global politics. Four of the biggest and most strategically important democracies in the developing world – Brazil, India, South Africa and Turkey – are increasingly at odds with American foreign policy. Rather than siding with the US on the big international issues, they are just as likely to line up with authoritarian powers such as China and Iran.

The US has been slow to pick up on this development, perhaps because it seems so surprising and unnatural. Most Americans assume that fellow democracies will share their values and opinions on international affairs. During the last presidential election campaign, John McCain, the Republican candidate, called for the formation of a global alliance of democracies to push back against authoritarian powers. Some of President Barack Obama's senior advisers have also written enthusiastically about an international league of democracies.

But the assumption that the world's democracies will naturally stick together is proving unfounded. The latest example came during the Copenhagen climate summit. On the last day of the talks, the Americans tried to fix up one-to-one meetings between Mr Obama and the leaders of South Africa, Brazil and India – but failed each time. The Indians even said that their prime minister, Manmohan Singh, had already left for the airport.