We all pretend that ‘negative’ political campaigning is bad but it works and it is good. A few weeks ago I listened to LSE students of political campaigning call on Hills to ‘go negative’ in the face of the Obama surge. She did and despite the polls still showing her behind, she won Texas and the crucial Ohio votes last night. [Great coverage here from the outstanding Houston Chronicle website – fantastic photo series]. She did it by pointing out in measured but unmistakable terms that her opponent was, as we say in sarf London, “all mouth and no trousers”.

This was a valid criticism. “Yes we can” and “change” are great slogans but he has studiously avoided answering any critique of his record or his policies. Narrative and aspiration are important in politics. Gordon Brown is in desperate need of both. But American politics is particularly competitive and that means you eventually have to go beyond rhetoric and undergo tests of substance.

Like Hillary, Obama is still standing and the race is still open. But as it gets closer to November it will get more real. And that should means the contest will now be tougher and sometimes ‘negative’. The Democrats fear is that it will spill over into animosity and leave a stain on their claim to the White House. But the voters obviously welcome a potential President who fights hard and talks tough.