By forcing Cameron to reaffirm his green credentials, the Labour leader skillfully drove a wedge between the PM and his party.
As the blue collar modernising group warns, a deal with UKIP would alienate the centrist voters that the Tories need if they are to ever win a majority again.
Chris Leslie's pledge to avoid the wasteful short-termism of the coalition is a good place to start. But far tougher choices lie ahead.
After withdrawing from the centre-right European People's Party grouping, Cameron has no right to tell his MEPs not to flirt with the anti-Euro Alternative für Deutschland.
Labour tribalists and the media would immediately demand that Miliband follow the PM and promise to govern alone after May 2015.
Any minority government would soon collapse as there would be no impetus for the Lib Dems to support the Queen's Speech.
The Scottish First Minister says that "while I was compiling the oil and gas index, David Cameron was still fooling around on the playing fields of Eton".
There is no guarantee that fair distribution of opportunity will even be a factor in the election.
The lack of government legislation is so great that ministers are now constantly increasing the days allocated to Opposition motions.
The PM's piece on welfare reform makes no reference to Iain Duncan Smith's troubled programme.