A yes for the alternative vote resolves a psephological tussle for me. But Labour has more pragmatic considerations
If you interrupted a card game and asked players for their take on whether the ace should be the most or least valuable card, you wouldn't expect disinterested replies. As in cards, so in politics: views on the rules are entangled with the desire to win. To stick with the imagery of cards, with the alternative vote this is true in spades.
The modest reform on offer in May's referendum – on which the latest Guardian/ICM poll suggested the public may now be souring – is one that only nerds start out with strong opinions on. It is not proportional representation, which would transform things by necessitating perpetual coalition, but a tweak to allow voters to deploy second preferences after their favourite candidate has fallen away.
Its origins lie in the grubby deal that founded the coalition, now known as the voting system and constituencies bill. In return for their chance of AV, which the Liberal Democrats initially hoped would hand them 30-odd seats at Tory expense, the Conservatives demanded the "constituencies" bit, which shrinks the Commons and could abolish 30-odd Labour seats. Cut out from the trading, Labour filibustered the legislation, even though its own manifesto had promised a plebiscite on AV.
Now, I happen to be one of those obsessed with the rules, and as such I see AV as worthwhile because it resolves the psephological tussle between heart and head. It would allow stereotypical Guardianistas to vote green, safe in the knowledge that they could transfer their allegiance as needed to keep the Tories out; and it would also free up Guardianistas' rightwing counterparts to dabble with Ukip without fear of letting Labour in. But given the murky origins of the proposal, most political players will want to judge this trifling rule change by what it means for their own side.
With the Liberal Democrats (pro) and Conservatives (anti) split along strict party lines of perceived self-interest, the real question here is for Labour. For some MPs the way the cards fall on their own patch is pertinent. Emily Thornberry, not an instinctive stick in the mud, is wielding a megaphone for the noes – aware, no doubt, that Tory transfers to the Lib Dems under AV would have finished her off in Islington South last year.
Until recently, however, I would have said that most Labour antis were allowing their urge to give Nick Clegg a bloody nose to overpower rational judgment. Lib Dem and Labour voters have usually been closer to one another than the Conservatives, and over most recent history would have swapped second preferences for mutual benefit. Transfers between reds and yellows might have denied John Major's 1992 win, and the great tribalist Gordon Brown embraced AV to dish the Tories – by lending Labour support to the Lib Dems in southern seats that his own party could never win.
It might have worked, too, had not the fact of coalition intervened. It has triggered a mass defection of left liberals, leaving an electoral rump that leans to the right. The remaining Lib Dems have told recent surveys that they would prefer Conservative to Labour in a straight choice. As the campaign got under way, a new YouGov poll found that many Conservatives would transfer to their coalition partners, and that the many Lib Dems would reciprocate. Meanwhile, Labour voters are now in such an almighty sulk with Clegg that they would prefer to transfer to the Greens – or even to Ukip – than do anything to help him.
Consequently the poll predicts no net Lib Dem gains from a Conservative party whose overall representation would be unchanged. With Tory help, however, the Lib Dems would pick up a baker's dozen of seats from Labour, trimming its currently projected majority from 60 down to 34.
Other polls may refine the picture – having changed once, the electoral facts could well change again, and Labour also needs to weigh the dangers of setting its face against political change. Nonetheless, the Guardian/ICM poll found that the haemorrhaging of reformers is most pronounced among 2010 Labour voters. Whatever the arguments of high principle, in the immediate scramble to declare full house against the coalition, the low politics are now pulling the other way.