Back on Defense

Not surprisingly, Edwards and Obama were happy to continue conversation on Iran. "Senator Clinton and I just have an honest disagreement about this, but a very strong disagreement," Edwards said. "I think it's very clear that Bush and Cheney have been rattling the saber about Iran for a very long time, and I said very clearly when this vote took place on the Iranian Revolutionary Guard that it was important for us to stand up to them."

Obama followed suit. "What I've been consistent about was that this saber-rattling was a repetition of Iraq, a war I opposed, and that we needed to oppose George Bush again," he said. "We can't keep on giving him the benefit of the doubt, knowing the ways in which they manipulate intelligence."

Will the intraparty skirmishing help clarify the choice for Iowa voters—or turn them off?
The conventional wisdom is that they dislike negative politics and punish candidates who are overly aggressive—as they did Howard Dean and Dick Gephardt four years ago.

But Tom Vilsack, Iowa's former governor and the co-chair of Hillary Clinton's campaign, believes the give-and-take is not only above board but favors Clinton. "Iowans want to know what the differences are between the candidates," he says. "They want to know the contrasts."

And yes, says Vilsack, one big contrast is on Iran. "Here's the difference: she was there. She actually cast a vote," he said, referring to the fact that Obama missed the Senate roll call while out campaigning. "There's an issue with a guy who was a state legislator who votes 'present.' You vote 'present' when you have a conflict. This is a guy who does a pretty good job of not answering questions. A guy who skips a significant vote to campaign. It's an issue. He can be critical of her voting, but at least she was there and is willing to stand up and explain what she did. It's very easy to criticize somebody when you weren't there." (Obama has since called his missed vote a mistake.)

The Obama campaign seems to be taking the attacks in stride. "It would be hard to respond in kind," says Gibbs, "because there are five attacks every day. They are emptying the gun every day. As Senator Obama has said, we have entered the silly season. And the silly season began with a slide in the polls. We think there's a premium on continuing to talk about what people really care about."