No electoral system is perfect. First Past the Post has its advantages and it's a mistake to suppose that switching to the Alternative Vote or multi-member constituencies elected by STV solves all problems. On the contrary it probably replaces one set of difficulties with another.
Nevertheless, one wonders how sustainable FPTP is. Traditionally it has done a pretty good job of corralling extremism and producing more-or-less coherent governments that can command a majority in the House of Commons (and that can be unceremoniously turfed-oot once they've outlived their usefulness). Unfortunately - and increasingly - those governments enjoy only minority support in the country-at-large. Political allegiance is more fluid and conditional than once it was and it seems clear that many voters don't feel as though they're included in the mainstream conversation.
Consider that in 1970 the Tories and Labour combined to win almst 90% of the votes cast. But by 2005 they won just 67% of the votes and they seem unlikely to do very much better than that this time either. This doesn't matter so much if elections are viewed as a means of electing a parliament from which a government is subsequently formed; it is a problem, however, if the election is seen as a kind of plebiscite fought by rival would-be Prime Ministers seeking a personal mandate. This latter view is increasingly, I think, popular.
Many Conservatives seem to believe that any kind of PR system would mean permanent centre-left government but this seems unlikely, not least since one cannot think of any similarly major western democracy, using any electoral system, in which the right has been excluded from power on anything like a permanent basis. Perhaps Britain would prove an exception; more probably the political arithmetic would change in ways that are as yet unpredictable. Depending on the system used, of course.
If choice is a conservative virtue - and in many ways it is - then there must, one would think, be a properly conservative case for changing the electoral system so that more people may take up the Tories (kind) offer to join the government of Great Britain.
I'm not sure what the best system would be (and I don't really object to FPTP either) and I can see why a new government might not wish to become embroiled in a long discussion about electoral machinery but a party that embraces diversity and referendums ought to be able to contemplate a discussion on these matters with some degree of equanimity.
Electoral reform didn't matter a damn when the Big Two won nine in ten votes; if they only win six in ten then matters seem rather different and you have an awful lot of people sitting on the sidelines, frustrated and feeling ignored and shut-out from the conversation.
Perhaps 2005 and 2010 are blips and the Big Two will regain their former ascendancy but looking around europe I'm not sure that's likely. Politics is a fragmented, disenchanted business everywhere as old voting blocs crack and splinter and new arrangements need to be found and met.
To repeat: there doesn't seem to be any good principled or philosophical reason for the Tories to oppose a voting reform discussion. Which is, of course, another reason why they should, privately, send a message to Nick Clegg indicating their willingness to talk.
And who knows, perhaps the punters would vote to keep FPTP anyway?
UPDATE: Tom Clougherty has a good post on this too.