Writing a century ago, Sidney Low noted that the easiest way to get a round of applause at a public meeting was to claim that something was non-partisan. "No sentiment," he said, "is likely to elicit more applause . . . than the sentiment that 'this, Mr Chairman, is not a party question, and I do not propose to treat it from a party standpoint'." Reaction to Michael Howard's comments on abortion suggests little has changed. According to a YouGov poll for the Daily Telegraph, almost 60 per cent of the public doesn't see abortion as an appropriate subject for debate between parties - compared to just 28 per cent who do - and most politicians don't want it to become an issue in the election campaign.
Most British elections have usually eschewed debate over what are typically called "issues of conscience", largely because the parties usually give MPs a free vote on them. But though such issues are said to cut across party lines, that is not the reality when it comes to the voting. Look at the 1990 votes, which gave us the current abortion law, with its time limit of 24 weeks. Two-thirds of Labour MPs voted to keep the limit at 28 weeks - compared to just 5 per cent of Conservative MPs. The more restrictive option of 22 weeks was supported by 64 per cent of Conservatives, but just 15 per cent of Labour MPs. Even without the whips' dictates, MPs' party labels were the most significant predictors of how they voted. Other influences - such as younger MPs tending to be more liberal, Catholic MPs being more likely to vote in favour of restrictions, and women being more "pro-choice" - are both sporadic and partial.
Since 1997, and nearly all on free votes, handguns have been banned, gay rights extended, the law on stem cell research liberalised, contraception made more easily available, hunting with hounds banned, and the death penalty finally abolished (it remained a theoretical option for a few offences). Some will applaud these changes, others deplore them. But they happened, not by chance, but because of the party composition of the Commons.
In an era when people complain of party convergence - "they are all the same" - such issues provide examples of the differences that remain. It is misleading to pretend they have nothing to do with party affiliations - and undemocratic to say they shouldn't be discussed during an election.
Philip Cowley is reader in parliamentary government at the University of Nottingham