If there is one thing they can take from the coming disaster, next year's results are likely to be "trough LibDem". It cannot get much worse. The problem is that the brick wall is coming, the collision is inevitable - but there are things that can be done to ease off on the accelerator. And signalling opposition to the hated bedroom tax is just one of those late-in-the-day things. To detoxify they need to put clear water between themselves and a Tory party whose nastiness is matched only by their determination to drag Britain down the plug hole.
As anyone who's sought therapy will tell you, saying you're going to change is easy. Carrying it through is something else. Courtesy of Labour, the bedroom tax is to be the subject of another Commons vote in the autumn. Here's the chance for the LibDems to act according to their conscience. Will they?
It has all the makings of a political crisis. For the Tories the bedroom tax is a point of principle: they believe it's popular (it isn't, and opposition is hardening) and will fight tooth and nail to retain it as part of their Dickensian assault on the poor. So Clegg has a choice: to take the coalition to the wire and potentially break it, or take the first significant step to detoxification. For let there not be any doubt. Just as breaking manifesto promises on tuition fees did the LibDems, so a heroic stand, of putting principles before eight months longer in ministerial seats could help them turn that corner, and make a deal with Labour a wee bit less unpalatable should the electorate gift Westminster a hung Parliament again.
From here flows further political opportunities. The lead up to the election introduces a new dynamic into the mix and one so-called professional commentators still haven't picked up on. That is two parties will be scrapping over their record in government. Already, of the coalition the LibDem narrative is one of tempering the Tory party's worst impulses, of trading acquiescence to bad things as the price of some "good things". The LibDems here would point to the Pupil Premium, raising of the tax thresholds for the lowest paid, and, yes, the fact students don't have to pay exorbitant fees up front. The backdoor privatisation of the NHS, the work capability assessment debacle, cutting tax for the very richest - the LibDems are rather less keen to be associated with these. However, punting that message between now and next May is easier for the depleted activist pool to deliver if there is demonstrable evidence of change behind it.
There is a clear party interest in pursuing this course, yet I expect Clegg will order his troops to abstain and/or stay away from the Commons. Partly because voting against it makes the parliamentary party look like hypocrites, partly because - actually - some LibDem ministers have relished their time in government and are willing to stay there as long as possible for any price, partly because of the Westminster parlour game - do the LibDems want to be seen falling behind a Labour "stunt"? And lastly, there's Nick's self-interests too. If by the skin of his teeth he hands on in Sheffield Hallam, what future awaits? A return to opposition or coalition with Labour limits his prospects somewhat (Tim Farron or an unlikely comeback from Charles Kennedy put pays to that). However, another coalition or confidence and supply arrangement with the Tories might keep him safe.
So then LibDems, what's it to be? The short sharp shock of breaking the coalition over the bedroom tax, or an absolute pummelling later on?