One of the key Labour lines to take after last night's debate has been to agree that Nick Clegg did really well, and that Cameron did 'surprisingly' poorly. This is partly because it is virtually impossible to defend Brown's performance (although listen out for stuff like "he showed he's got substance", which is a euphemism for the fact that he is hopelessly unable to communicate with ordinary voters). It is also part of a natural Labour desire to do down their most serious rival. But could there be more to it? Could there be a good strategic reason for boosting the Lib Dems?
There is an understandable strategic explanation behind the Labour love-in with Clegg. The first one is election based, the second is a post-election assumption of a hung parliament. As regards the election, the Lib Dems actually pose a minimal threat to the Labour party. In 1997, when the Lib Dems received the parliamentary boost that they have more or less maintained in the subsequent general elections, they achieved it mainly at the expense of the Conservative Party. If they have considered that they may not experience a significant increase in the number of seats they win at this election, the Lib Dems have at least decided to put all of their effort into maintaining their current seats. This is primarily an anti-Tory effort - the more of their 1997 seats that they hold, the fewer gains will be made by the Conservatives (see the battles in Westmoreland and Lonsdale, or Sutton and Cheam, or Richmond, for example). The Lib Dems have acted as a middle class safe haven for anti-Tory voters since 1997, and they aim to continue to do so. Even many of their city seats - like Clegg's own in Sheffield - were actually gained at the expense of the Tories. The Liberals are much less effective in the 'urban poor' areas held - often on low votes - by Labour. So a good Lib Dem campaign is likely to hinder the Conservative advance, and that is an obvious benefit to Labour. Quite where the protest vote against Labour in the more deprived seats should go is another question, the answer to which is too often the BNP, but that is another issue.
The post-election strategy is, of course, to try and line the Lib Dems up as potential Labour allies in an anti-Tory parliamentary coalition in the event of a hung parliament. This represents an acceptance in the Labour Party that they are not going to win a majority themselves, despite the electoral system's inherent bias in their favour, and that their next best option is a hung parliament in which the Conservatives can be out-voted by a 'coalition of the left'. Quite how happy Nick Clegg would be to keep Labour in power is an open question, and his irritation in the debate at being called into agreement by Brown so often may be a sign of his reluctance. After all, the Lib Dems are still smarting from their recent coalitions with Labour in Scotland and Wales, which were rejected in the devolved elections. If any such alliance were even to be possible, it seems likely that the first price exacted by a resurgent Liberal party would be Gordon Brown's removal as leader. The second should certainly be electoral reform.
Where, in the meantime, does this leave David Cameron? Well, where he's always been actually. Faced with an uphill electoral struggle that requires him to gain Lib Dem as well as Labour scalps in the election. The post-election dilemma of a Conservative Party that fails to win power will, of course, be acute. Despite the anti-Tory vote heading towards the comfortable centre-left represented by the Liberals, a defeated Cameron would be likely to face short shrift from a party which would actually be determined to reassert its clear right-wing credentials. The party's right-wing leaders will not have been oblivious to the fact that Cameron scored high positives in the debate when he spoke of school discipline, a cap on immigration, and strong action on crime. This, they consider, is natural Tory territory, rather than the pro-NHS, One Nation Green agenda being pursued by Mr. Cameron.
NB: Tory blogger Iain Dale takes a different view of a possible Lib Dem resurgence, believing it could actually benefit the Conservatives.