Nick Clegg is taking his liberal principles to their logical conclusion and speculating about supporting a Conservative government.
The problem will be the two parties members - who spend most of their time opposing each other. The campaigning style and tactics of the Lib Dems are especially despised by the Tories ( and Labour for that matter ) and the Lib Dems often present themselves as an alternative party of the left.
Sparks are likely to fly.
Update: And here they are:
"A senior Liberal Democrat MP warned that Mr Clegg's move could split the party. He said: "I am pretty annoyed, to put it mildly. He hasn't discussed this within the parliamentary party. It would take some swallowing for the majority. We knew he was going to be like this. We knew he would be a maverick putting forward frankly right-wing ideas. There are a very significant number of centre-Left politicians who would find it totally unacceptable."" - Quoted in the Daily Mail ( From Conservative home ).
I suspect the truth is many Lib Dems thought they were only ever in politics to govern with Labour at the national level. The dynamics of this are going to be intresting.
Nick Clegg is perhaps trying to avoid the mess they made in the Scottish and Welsh devolved governments by just being Labour's hired help. But it won't go down well with the yellow groupies.