Martin Kettle: The reform bill fiasco has vindicated the militant oppositionism embodied by Ed Balls and Labour, and may yet threaten the coalition... Put big constitutional reform on the agenda at the start of a parliament when authority is high, not halfway through, when authority is slipping away. Hold a referendum first, on the principle of the thing, so that MPs are cowed and rebels have less room to make mischief. Don't go to a referendum afterwards, when the vote becomes a verdict on the government not the reform. Nick Clegg should have learned from that.