Mitt Romney won the debate tonight. He was more focused, specific, energetic and prepared than President Obama. The Obama campaign's silver lining was in what he got Romney to be specific about. Expect, for instance, that Romney's admission that he will voucherize Medicare to make its way to ads in swing states near you.

Marvin Joseph/Washington Post

But for the most part, this debate was where Romney's strategy of being purposefully vague about the nature of his policies paid off. The first third of the debate was an argument over the missing numbers in Romney's tax plan. Romney fiercely objected to Obama's characterization of his tax plan as a $5 trillion tax cut. After all, he says he'll pay for all of it, somehow, later. And he won't permit what is, on paper, a huge tax cut on the rich to cut taxes on the rich. So if you take what's on the page, the cost is $5 trillion and it's a huge tax cut for the rich. If you take what Romney says will eventually be on the page, the cost is...nothing. 

Elsewhere, Romney insisted that he had a "lengthy description" of his health-care plan on his web site, and seemed satisfied when Obama didn't challenge the comment. Romney's description of his health-care plan is less than 400 words, or about half the length of a typical op-ed column. But there's enough there that Romney could say he has a plan for people with pre-existing conditions, even if it's not clear how that plan would work, or whether it's any different than what the law says now. As for what he'd do about the uninsured, that also wasn't very clear.

The same was true on Wall Street reform, where Romney insisted he opposed Dodd-Frank and promised to replace it with...something. And on spending cuts, where Romney said he would balance the budget but didn't offer many specific cuts beyond eliminating funding for PBS. 

Romney also executed his overdue pivot to the center, and he did it in an especially savvy way: He sold himself heavily on his experience working with Democrats in Massachusetts. This solves a very particular problem Romney has in talking about his record in Massachusetts, where he governed in a way that swing voters would like, but he signed a slew of policies conservatives hate. Since Romney doesn't want to alienate conservatives, he's largely left Massachusetts out of his campaign.

Tonight, however, Romney found a middle way. He ran on his success working with Democrats rather than on the specific policies he worked with Democrats on. Since Romney is likely to face a Republican Congress if he's elected president, conservatives don't need to worry, at least in the short-term, that he'll eagerly cut deals with congressional Democrats -- after all, doing so would lose him the support of the House Republicans.

But since ordinary voters rarely factor in the future composition of Congress when listening to presidential candidates, what it sounded like Romney was saying was that he would run an administration based on bipartisan compromise. In this, Romney was able to have it both ways, and he knew it. At another point in the debate, he attacked Obama for not supporting the Simpson-Bowles proposal, which would've been a mark of bipartisanship, even as he admitted that he himself opposed the plan. 

In this debate, Romney's strategy of offering a little detail and leaving out a complicating facts served him well. It largely confused the differences between the candidates and it kept Obama off-balance. Romney matched that with crisp, clear answers and an easy demeanor. It was, as the snap polls seem to be showing, a win for him, even -- and perhaps even because -- it was a loss for those looking for more clarity on what he would actually do as president.