Oh, sure, the rise of the Liberal Democrats is a problem for the Conservatives too and it doesn't help their chances of securing an overall majority. But it may be an even bigger problem for Gordon Brown. Can anyone really remember anything Labour have said since Thursday's debate? Not really. It's as though Labour have been erased from the campaign entirely, leaving the field to the Conservatives and the Liberals.
The Cleggathon has had another effect: it reinforces the case for change and strengthens and deepens the media narrative about change. This too must cost Labour dear. The media has constructed a campaign story that accepts that change is a given and all that we're doing now is haggling over the details.
For years the Lib Dems have complained, with some justification, that they are ignored by the press. But that's party because a two-horse race is much easier to dramatise and explain than a messier, more complicated three-dimensional contest. Now, however, the Lib Dems are in the race and it is Labour - and Labour's message - that is being ignored.
From this it also follows that the more thoroughly Labour is eclipsed so it becomes harder for Clegg to do a deal with a discredited party even if it's led by someone other than Gordon. Clegg's own legitimacy, however threadbare you may think it, depends upon being seen as the Change Guy. But you can't be the Change Chap and sleep with Labour and so, curiously, it may be that Clegg's success, if it endures, actually ends up by limiting, not increasing his options.
If the Liberals came a distant third in a hung parliament it might be easier for them to support Labour than it will be if they come second in terms of voting share. Labour, on the other hand, are fast assuming the third parties traditional role of being the party that will, and can, promise anything...
Perhaps this is mistaken, but it seems to me that for many people Labour are now the afterthought and it's the Liberals who will discover that being one of the top two brings with it complicating responsibilities and a whole new level and type of expectation.
Regardless, the case for ditching Labour has been cemented and deeply embedded in the national consciousness these past few days and it's hard to see quite how Labour can counter, let alone reverse, that impression. Then again, there are still more than two weeks til polling day and Anything Can Still Happen. And Might.