John Edwards: It's not the sex, it's not the lying . . .

It's the denial of responsibility.

John Edwards admits what has been rumored for a while, that he had an affair. The usual questions and issues raise their ugly heads - is this a private matter? Should it just be between him and his wife, Elizabeth?

My answer is no. John Edwards made the decision to run for public office, which put him in the spotlight. He made the decision this year to run again for the White House, which requires asking millions of people to put their faith in him. That makes his conduct an issue for the public. If he didn't want his personal life to be a matter of public discussion, he shouldn't have run for office.

It's also a matter of lying about the actual affair. Lots and lots of politicians all over the world, throughout human history, have had affairs. But that still doesn't make it OK.

Politicians are human. They will screw up. We cannot expect them to be perfect.

But we can expect them to take responsibility for their mistakes. When Bill Clinton admitted, at the start of the 1992 Presidential campaign, that he and Hillary had had "problems in their marriage," he was admitting that he had been unfaithful, but he was also taking responsibility. So he was forgiven by enough voters to win the Presidency. We knew he was a player. But we made an implicit bargain with him: keep your pants on for eight years, and all will be fine. He didn't, and then lied about it. It's not the sex, or even the lying - it's the denial of responsibility.

There are ways to deal with this kind of thing that do not involve denying responsibility. The Mayor of LA, Antonio Villaraigosa, separated from his wife a while ago. But he held a press conference and basically admitted it upfront. He also moved out of the Mayor's mansion. And he has been mostly forgiven by the public. It's awkward to talk about taking a "classy" approach to adultery, but insofar as that is possible, that's what he did.

The implications of Clinton's affair should have made Edwards particularly wary. It's entirely possible that Al Gore would have won in 2000 if not for the lingering anger over Monica Lewinsky. Personally, the prospect of seeing Bill Clinton back in the White House was a big reason for my reluctance to back Hillary, before I committed to Obama.

Au revoir, Mr. Edwards. Hope you like that nice big house.