Brown has just resigned as PM. Alex Massie sees the logic of Clegg's actions over the past couple days:
Once Labour MPs vowed to derail any plan to force through voting reform without a referendum and once John Reid, David Blunkett and Andy Burnham pointed out the absurdity of a "Loser's Alliance" that, however constitutionally permissable, would mock the actual, you know, result of the election then even the most sawdust-brained Liberal Democrat MP could appreciate that this bird wouldn't fly.
That leaves a proper deal with the Tories the only sensible option - an outcome that I suspect was Clegg's preference all along. But he may now have been able to sell the idea to his party without having to make it a confidence motion in his own leadership or having to issue an ultimatum to his party. That leaves Clegg in a stronger position internally.