Obama has received a bounce in the polls from his convention, and though we'll have to wait a few days to know for sure, it looks quite sizeable. That narrow gap is widening, which makes Romney's uphill battle all the steeper - at this stage, the challenger should be several points ahead to have a decent shot at victory in November.
It's extraordinary for an ex-president to be able to make the political weather like this. Having already paid tribute to Clinton I won't here marvel at how the talents and tenacity of the man himself made this possible, or discuss Obama's belated realisation that it was worth making the effort to get Big Dog fully onside. Instead, let's consider the other politician responsible for making Clinton such a potent force in this election: Mitt Romney.
You can see why the Romney campaign did this - the aim was clearly to reach independent voters who like Clinton, aren't naturally Republican, but aren't sure about Obama. One consequence of this strategy, however, was to reinforce the perception among voters that Clinton is an authoritative, non-partisan arbiter of this election and of economic and social policy in particular.
Hmm, now how could that possibly go wrong?
On Wednesday evening, of course, the grenade blew up in their faces. And given how much Clinton is enjoying himself, it is going to keep blowing up in their faces, every week, from now until November 6th.