Testing the waters
Extraordinary, quite extraordinary. Anyone listening to David Miliband taking phone calls on Radio 2's Jeremy Vine show could be in no doubt.
This is a man testing the waters for a leadership bid and a man simply unprepared to come to the defence of a beleaguered prime minister.
Even when listeners poured abuse on Gordon Brown the most the foreign secretary could bring himself to say was that he was a prime minister in difficult times, that he had huge experience and good strong values - not exactly the warmest endorsement of the man who leads his party.
What's more, when listeners said how much they liked him he merely giggled and made jokes that these were not his friends or his mum who'd been paid to ring up - in other words he took all the praise and did nothing to deflect the abuse headed in Mr Brown's direction.
Whatever David Miliband's original intention was he has now begun a process where the country and his party will begin to judge whether he is a good replacement for Gordon Brown. It won't be long until some newspaper commissions a poll as to whether voters prefer him to Mr Brown.
If there is a Miliband poll bounce which is quite likely given the favourable publicity he's had and the extraordinary unpopularity of the prime minister, Labour MPs will begin to assess whether he's the man who might save their skins. In other words this will produce a momentum of its own.
Many cards remain, of course, in the prime minister's hands. On returning from holiday he could demote Mr Miliband, he could give him the poison chalice of the chancellor's job, or he might produce a new policy plan to regain the political initiative. However he will do so against the background in which for the first time since he faced Tony Blair, a genuine rival has emerged.