Indeed, things could get messy for Brown in just a few hours time. You'd expect him to win the vote, what with Labour's majority and the creeping sense that Downing St very much wants this to happen. But even the slightest hint of a Labour rebellion, or of Lib Dem disquiet, and the story could turn toxic for the PM. Then, rather than being about Brown the Reformer, it could all reduce down to questions of party discipline and commitment. Not ideal, with a general election only weeks away.
But even if Brown pulls it off comfortably, he's not assured of success with the wider public. There's every chance that they'll see Brown's newfound zeal for voting reform for what it is: a cynical "deathbed conversion," designed to create the impression of action, action, action. And, besides, have the public really been waiting, hungrily, for a chance to have their say on one particular voting system, chosen by politicians, over another? Hm. When it comes to renewing our democracy, Brown may have been better off paying attention to some of the "smaller" issues; mentioning expenses in the Queen's Speech; not dithering over his party's receipt offenders, and so on.
Much will come down to who wins today's spin war. Labour will try and claim that the Tories are getting in the way of the Most Significant Reform of our Times, while the Tories will say that fiddling around with alternative votes shows how the government just Doesn't Really Get It. In that respect, Cameron took an early lead with a mostly well-judged and well-framed speech on our democratic deficit yesterday. Of course, as Rachel Sylvester argues today, all parties have much further to go on this - but there's still a sense that Brown is dawdling some way behind his Tory counterpart.