Does a politician's private life matter? Yes.
Should a questionable private life prevent a politician from achieving high office? No.
Somewhere in the grey between the answers to those two questions is where a grown up society should be.
Here are six factors that can help guide us through that grey:
Externalities: Private lives have public consequences. Only today, for example, a judge is telling us that a "meltdown" in relations between parents and children is driving most of our greatest social problems.
Hypocrisy: It's hardly helpful that Al Gore preaches environmentalism to all of us but doesn't exactly practice it himself but I'd prefer hypocrisy to indifference. As I've blogged before, I'd prefer a politician who tries to be green in his private life than one who doesn't care about green issues at all.
Regret: I don't think it's quite enough for a politician to say that illegal drug use, however long ago, is an entirely private matter nor that the fact they have three families is none of our business. Drugs and family breakdown are major causes of today's social problems. We don't have a right to peer into the nooks and crannies of a politician's past or home life but I'd like to hear politicians regret drug use and regret father absence.
Consistency: Some people want to brush certain private behaviours under the carpet but are fascinated by others. One friend of mine says that a person's sex life or drug history is completely irrelevant to their public persona. She's also told me that she'll never vote for a Prime Minister who prays to God.
Generosity: Who amongst us has not failed in our private lives? We shouldn't have a culture that delights in personal failings and ends up discouraging good but imperfect people from entering public life.
Realism: Sometimes a person's devotion to public service has damaged their family life or driven them to certain excesses. History has clearly taught us that flawed fathers or people who drink too much can be great Prime Ministers or Presidents.