In reality, the summit probably will give Brown a bit of a boost. It will allow him to play the statesman on the world stage and associating with Obama can’t hurt. (Although the idea of a joint Brown-Obama Wembley rally, which reportedly made it to the memo stage, is an idea that is as crass as it is desperate.) But the summit isn’t going to transform British politics, and is unlikely to produce something that resonates with the electorate—international regulatory reform is hardly the kind of thing that excites swing voters.
Even Peter Mandelson, master of the darks arts that he is, seems to be falling into this trap. In his prepared remarks at the Council on Foreign Relations in New York, Mandelson, rightly, said that the “political dilemma” is “we need high level meetings and action, which generate big expectations which, in turn, trigger disappointment and market reaction when immediate results are not produced.” But a friend tells me that later in the session, he declared that "we have to make sure the London summit is a turning point".