Time’s Michael Scherer argues that criticizing a politician’s old votes when they’re easier to attack than their new proposals is unfair. Here’s what he says:

Here’s an old political consultant trick: You want attack your opponent for supporting Policy X, because your pollsters tell you such an attack would help your candidate. But there’s a problem. Your opponent doesn’t clearly support Policy X. So you send off researchers to find an old legislative vote that you can use in an ad to mislead the public about your opponent’s plans, without lying outright. Instead of saying “My opponent supports Policy X,” all you have to say is “My opponent once voted for something that sounded a lot like Policy X. Be very afraid.”

I don’t necessarily agree with him that this is necessarily unfair. To show that I’m not just being an Obama partisan on this, let me provide an example that pertains to my preferred candidate. Obama’s tax plan promises to lower taxes for everyone making less than $250,000. Sounds good to me, but campaign promises are cheap. I think McCain is perfectly justified in going through Obama’s voting record and arguing that given his history, this is a promise he is unlikely to keep. (McCain’s people constantly claim that Obama is going to raise taxes on the middle class, and the Obama people argue that they’re lying because Obama has promised to lower their taxes. I think there’s space to confront a candidate with their own legislative history as long as it’s done honestly.)

I think it’s out of bounds to intentionally distort your opponent’s record. For example, the claim that Obama supported sex education for kindergarteners was dishonest and unfair.

But if nothing else, if a policy you propose differs with the votes a politician has previously made, they ought to be obliged to reconcile their voting history with what they claim they want to implement.