Nick Clegg has just refused to confirm to Andrew Marr whether proportional representation is a "precondition" of any alliance with Labour or the Tories. What this tell us is that the Lib Dem leader is still very willing to do business with David Cameron.
It's just about conceivable that Labour could be persuaded to offer Clegg proportional representation in return for his support in a hung parliament, but there's no chance of the Tories doing so. Cameron has rejected electoral reform on principle, arguing that PR "takes power away from the man and woman in the street and hands it to the political elites". Thus, for Clegg to describe PR as a "precondition" of any coalition government would be to rule out, in effect, a partnership with the Tories.
The decision not to do so reflects that he is more angered by Gordon Brown's limited support for reform than he is by Cameron's outright opposition. As Patrick Hennessy reports in the Sunday Telegraph, Clegg regards the promise of a referendum on the alternative vote (AV) -- a system that could prove even less proportional than first-past-the-post -- as "worthless".
From the Lib Dem perspective, no reform is better than bad reform. A vote in favour of AV would lock the country into that system for the foreseeable future, a frightening prospect for the Lib Dems. Cameron's anti-reformist position may turn out to be the more canny one.