Quote:
...set a date for your own government to be most likely weakened by the PR followup
I think that's one of the major impediments to change without cross-party support. As soon as any party starts to believe it could command a majority, the inclination to introduce a fairer system wanes fast. And if they're
in power, all the more. Cf. what Smiffy just said re: Canadia. I imagine that any smaller parties offering a pact to support an electoral reform-supporting Labour party (or electoral reform-supporting Tory party, I guess, should hell freeze over) would try to bake the commitment in before they found themselves in the position to break their word.