Romney won, Obama lost and the campaign is far from over

Where has this Mitt Romney been? And where did that Barack Obama come from?

At Wednesday night's debate between the Republican nominee and the president, it was Mitt the Likable Moderate who showed up: relaxed, in command of details, hair carefully tousled, offering kind words for both Democrats and government regulation. The president, on the other hand, was verbose, weary, occasionally peeved and seemingly ill-prepared. The Twitter consensus, formed before Obama had finished his first answer, is that Romney won decisively.

We don't disagree. Now the question is how, if at all, his victory will change the remainder of the campaign.

There are several ways to score a debate. Some suggest watching with the sound off, on the theory that a candidate's body language communicates better than his words. (We may try this next time.) Then there is the rhetoric: Who got off the most zingers? Were there any gaffes, and were they genuine? Wednesday night's debate provided precious little material on either score, although Romney had a cute quip about how honored he was that the president was spending the night of his 20th wedding anniversary “here with me.”

Then there is the radical notion of actually assessing what the candidates say about the issues they are debating. This, however, turns out to be sort of complicated.

A case in point: Obama repeatedly criticized Romney's plan for a $5 trillion tax cut, which would explode the budget deficit. “I don't have a $5 trillion tax cut,” Romney said. OK, fact-checkers: Who's right? As it turns out, they both are; the claim gets a highly unsatisfying “half-true” rating from PolitiFact. The problem is that Romney's tax plan is so vague that Obama — and the nonpartisan Tax Policy Center — has been left to fill in the details. Romney's plan contains no such figure, but it is a fair assumption from what he has proposed.

Good debate relies on facts, but it thrives on argument. That's probably the best way to judge the success of this debate: not just who got the better of his opponent in those 90 minutes, but how those 90 minutes will affect what the candidates say and do in the next 33 days.

We don't know yet, obviously. But Romney has clearly improved his ability to make his case to the voters. As he basks in his victorym, he should also note how he won: by playing more to the center than to the right, appealing more to reason than to partisanship. As always with Romney, there is the question of whether this shift is genuine. For now, conservatives are so ecstatic with his performance that they seem more than willing to put up with a little pro-government rhetoric.

Obama, for his part, may want to take fewer breaks from his debate-preparation regimen next time around. And by now, his campaign has read the liberal reviews of his performance, as withering for what he did say as for what he didn't — no mention of Romney's infamous critique of the 47 percent, for instance, or his tenure at Bain Capital, or his running mate's support of privatizing Social Security, and so on.

Obama can always console himself with the political science, which shows that presidential debates rarely affect the outcome of an election. (Although, to be honest, political science's list of things that don't matter is getting alarmingly long.) But politicians, more so than even journalists and certainly more than political scientists, have to at least pretend that debates matter. They owe their supporters, and their ideas, that much.

If one of the purposes of a debate is to get candidates to talk to instead of past each other, to clarify positions and highlight differences and reveal temperaments, then Wednesday night's mostly succeeded. The next debate, between Republican vice- presidential nominee Paul Ryan and Vice President Joe Biden, is scheduled for Oct. 11. May the best argument prevail.