My colleague Nick Cohen, in a recent New Statesman article, launched into Mike O'Brien, a former Home Office minister. Mr Cohen wrote that a "foul smell" came from Mr O'Brien partly because of his role in the Immigration and Asylum Act 1999. Mr O'Brien himself wisely refrained from arguing the toss on that Act. He merely pointed out that he had also helped to draft laws on racial harassment.
However, another Labour MP, defending Mr O'Brien, told me it was his "misfortune" to get the job of piloting the 1999 Act through Parliament.
Many saw this legislation as hostile to victims of persecution, even racist. The MP argued that whether this was true or not, no personal blame attached to Mr O'Brien. We could not draw conclusions about the minister's views or prejudices. He simply did his duty.
This may seem a peculiar way of looking at things. How could a minister take responsibility for controversial legislation without believing in it himself? But to politicians, there is nothing strange about it at all. They spend their lives defending policies they don't like. Swallowing their personal reservations and bowing to the party or government line is what they do. Ministers may argue their case in the privacy of Whitehall but, if they lose, must argue unreservedly for the opposite view. Or else we would have ministers resigning every week.
This explains why politicians often talk in curiously strangulated language; if they disagree with their own side's policies, they speak in code. It also, I suspect, explains why people feel increasingly alienated from politics. We live in a more individualised, uninhibited society in which we are accustomed to free expression of personal opinions and emotions.
Politicians are not exceptional in this. Barristers in court defend clients they suspect of being guilty. Journalists often adapt their opinions to those of their proprietors or readers. Teachers follow the national curriculum when they think it narrow and anti-educational. It is just that politicians have to dissemble more publicly than most of us.
All this can guide us on what to expect of the new Education Secretary, Ruth Kelly. She is a devout Roman Catholic who opposes birth control and abortion. Yet more than two-thirds of secondary teachers, according to a TES poll, believe children should be told how to get an abortion. More than 80 per cent believe they should be taught about contraception, including the morning-after pill.
Ms Kelly may argue in Cabinet against teaching birth control. If she loses, she will then get on with ensuring that such lessons go ahead and defend them in public. This will be her "misfortune".
Can it really work like that? Catholicism, despite its doctrinal rigidities, is a religion of give-and-take. Its followers are accustomed to bargaining with the Almighty, using priests as intermediaries. It may be a mortal sin to undergo, perform or procure an abortion. But I would guess that being a reluctant party to the spread of information may be allowed.
Some may say that, even if she were to save herself, Ms Kelly would endanger the immortal souls of thousands of children. It is, however, possible to argue that the more children learn about abortion, the less likely they are to seek it. Indeed, most campaigners for sex education claim - at least in public - that their goal is to reduce promiscuous underage sex. I am sure Ms Kelly is clever enough to embrace this position.
Peter Wilby is editor of the New Statesman