It was inevitable that whichever coalition partner lost out in the AV vote would be put under pressure by its members and MP’s to take a tougher line with the other. From the Lib Dem point of view, a number of members must be questioning whether the coalition is now worthwhile. They are perceived to have made some unpalatable compromises in order to join and maintain the coalition, and now the prospect of voting reform, which was their holy grail, has been removed.

From a deal making point of view though the difficulty for the Lib Dems is “what is their BATNA” – their Best Alternative to a Negotiated Agreement? If they leave the coalition and cause an election now at their current low ebb they may well be penalised at the polls. Is that a better alternative than sticking it out, in the hope that the economy improves and they finally get some credit with electors for the improvement? I would expect the Lib Dems to pursue the latter option, but be noisier about disagreements such as this one on overseas aid, so as to try and create some ideological distance from their coalition partners going forward…