Although on the face of it the most dramatic moment in Ed Miliband's speech was his comment on Iraq, and more particularly the bizarre exchange it triggered between David Miliband and Harriet Harman, perhaps of much longer-term significance was the almost throwaway confirmation that the new Labour leader would be supporting a Yes vote in the forthcoming AV referendum. There had been a growing sense that the battle for this very minor reform of the voting system was on the way to being lost, but to some extent that was based on the assumption that Labour were happy to sabotage the campaign now that they were no longer directing it. The prospect of a Yes campaign encompassing both the Liberal Democrats and a fresh Labour leader who may very well still be enjoying a political honeymoon perhaps tilts the probabilities back to a positive outcome.
All the same, the more thoughtful Liberal Democrats will surely be reflecting tonight on their party's short-sightedness back in May. One of the main excuses for refusing to seriously investigate a progressive alternative to a Tory-led coalition was that it was unthinkable to countenance allowing Gordon Brown to remain in office, even for a brief period. That might have seemed to make sense in the feverish atmosphere of the moment - but the perspective changes considerably now that we've reached the point by which Brown would already have been gone. For the avoidance of four short months of discomfort, the Liberal Democrats now face the prospect of having to endure four-and-a-half more years of coalition with a party that the majority of members will increasingly regard as very obviously the 'wrong' partner. To say that the ad hoc alliance between Clegg and Miliband to push for modest electoral reform is likely to make the Lib Dem rank-and-file feel a touch wistful is something of an understatement.
Marriages are often blown apart by a yearning for the greener grass on the other side - could the same thing happen to the Lib Dems and Tories over the next two or three years? Intriguingly, Ed Miliband himself doesn't seem to think so, with indications that he's digging in for the full five year long-haul. He may of course be right, but it's far from a certainty.