The trouble is that this isn't a very new or original conception of America's role in the world. In fact, it was also Bill Clinton's conception of its role in the world, at least before he wound up bombing Belgrade because he couldn't get any bilateral or multilateral organisations to do it with him. It also contains an important flaw: for much of the past two decades, it's proved impossible to get the United Nations to sign on to any international action – military, humanitarian, financial or economic – because the leaders of Russia and China, fearing the day when their own peoples may rise up against them, will veto or undermine almost anything that looks too much like intervention, whether sanctions on Iran or a no-fly zone in Sudan. Neither the president nor his defence secretary has shown much interest in Nato up until now either, generally treating the alliance as a boring obligation. In fact, the time for Nato to discuss possible reactions to a violent revolution in the Arab world was last month or last year.