What is David Miliband up to?

In any leadership election, David Miliband would undoubtedly be the front-runner. But he has always played a cautious game until now. He declined to spark a leadership contest against Gordon Brown last year, rightly calculating that he would lose and that it would diminish his standing in the future. Now, his excellent article in today's Guardian has created suspicions in a media anxious to pretend that an empty Westminster is riven with plots, that he is planning to challenge Gordon imminently. Michael White has a good take on it all on his blog (and a reminder that like most politicians, Miliband is heading off on his holidays). I think the most we can say is that Miliband is putting down a marker; but the thesis that he advances in his article is one that sets the minimum parameters for the Prime Minister in September for his conference speech, as much as it is the start of the Miliband leadership manifesto.