It is now clear that America’s decision to invade Iraq was a grave mistake. The US is searching for a way out of the war and a presidential election is in the offing. Under the circumstances, one might expect a passionate and informed debate to be taking place about America’s role in the world.

In fact, the foreign policy argument in the US is rather disappointing. It sometimes looks as if Americans are so shell-shocked by the debacle of Iraq that they are unable to think clearly or boldly. The presidential election campaign seems actually to be inhibiting debate, as candidates cautiously manoeuvre for position – and seek to avoid making politically costly errors.