If the Conservatives are feeling a bit two-timed by the Lib Dems, then they are refusing to show it. Michael Gove was pretty well pitch perfect on Sky and later on Newsnight when discussing progress, and acknowledged that of course the third party had every right to negotiate with whom it chooses. The Lib Dems themselves might want to have a care, of course, about how sullied their leader starts to appear if they don't make a commitment one way or the other pretty soon.
Meanwhile, the Lib Dem tactics, ably abetted by Gordon Brown's resignation, has brought a promise from the Tories for a referendum on the Alternative Vote. This is as far as they can possibly go, but to be fair it is as far as anyone can possibly go. There are sufficient numbers in the Labour Party prepared to vote down such a proposal if it is simply introduced as a bill, as Tom Harris made clear on Newsnight. Quite apart from that, there is also the minor point of perhaps consulting the people via a referendum on such a significant change in the operation of our democratic machinery.
On balance, the Lib-Lab option still looks a lot trickier than a Lib-Con one. Former Cabinet Minister John Reid who, let us not forget, represents a Scottish constituency, was pretty clear about why he thinks a Lib-Lab deal shouldn't even be considered. It doesn't on its own bring a majority, it looks like a coalition of the losers, and it requires nationalist support which, says Reid, would inevitably come at the cost of demanding that any public spending cuts fall on the English rather than equitably across the provinces. Reid knows this is a non-starter, as does his Scottish colleague Tom Harris, who also noted that there was no way many Scottish Labour MPs would want to enter a coalition with the Scottish Nationalists. The 'rainbow coalition' so beloved of Campbell, Mandelson, Miliband et al is beset with monumental constitutional difficulties that simply don't arise if the Lib Dems eventualy run with a Conservative alliance.
This is what happens with a hung parliament, and it's exciting stuff. Whether we get better government as a result remains to be seen. But if they want to try and keep some of the high ground they've spent the last few decades occupying, the Lib Dems will need to come to a conclusion pretty quickly.