Since when did we apologise for morality?

There are lots of reasons why people go into politics: the green leather benches; the comedy expenses; the failure to get the grades to work in banking … but most politicans at least pretend that one of the reasons is to do the right thing. Recently, though, it seems as though morality and politics have become, shall we say, distanced. And last week, one politician seemed to imply that morals have no place in politics at all.

Sir Menzies Campbell is usually one of the more sensible and likeable Liberal Democrats, but he made a strange account for his party on the Today programme on Friday. He'd come to deny rumours that the party is in a "critical state", so naturally he misquoted Mark Twain. Like the author, he said, "rumours of our death are grossly exaggerated". But what was odd was his reaction to the implication that the Liberal Democrats are no longer the party of the moral high ground.

"I'm not so sure about the moral high ground point," he said defensively. "It's an accusation which is frequently made. We're a political party, and not all political parties occupy the moral ground.... And in particular when you're in coalition, life is very different from when you're standing slightly apart in opposition. Could we have done better? I think that's one of the lessons that have got to be learned…"

Could he have done better? Well, he could have started by not calling morality an "accusation". Or reacting with such horror to the idea that a party might be moral. Or suggesting that morals are all very well in opposition, but not for a party with any actual power. I'm sure it was not his intention, but he made it sound as though "moral ground" is no place for politicians at all.

It was Niccolo Machiavelli who said that "politics have no relation to morals", but most MPs have the sense not to admit it if they use Machiavelli as a model. So how have morals got such a bad name? They're only ideas of right and wrong behaviour based on personal conscience. It's just trying to do what's right.

The sad affair of the Chris Huhne and Vicky Pryce trials is being described as a modern-day "morality tale". In a morality tale, characters embody human virtues and vices, and beguile the hero with their entreaties. The character of Justice is yet to act here, but we've heard from Arrogance, Fury, Deviousness and Freewill. This morality tale shows how hard it is sometimes to identify the "right thing", and find the courage to do it. It also says: "Judge not, lest ye be judged."

Politicians are as human as the rest of us, and of course they struggle to do the right thing always. But let's not release them from even trying. Since he's so keen on quoting Twain, here's another nugget for Menzies Campbell: "Always do what is right. It will gratify half of mankind and astound the other." The way politics is now, it would astound more than half the electorate. But I think that they would like it.