Mitt Romney's aversion to policy details has been an issue throughout the campaign and it paid off for him last night. And it's worth saying that in some important ways, I think this preference for haziness is actually correct on the merits.
At one point during the debate, Romney nailed this precisely by noting that the details of tax policy are something that Congress hammers out. The president has some enormous powers in the legislative process, but they're powers of agenda-setting and the ability to veto—not at all the power to delve deep into details. And indeed I'd say President Obama ended up having a lot of problems with his base that could have been avoided had not Candidate Obama made so many specific pledges that he had no real way to deliver on.
Rather than demanding more specifics, what I wish is that reporters would press candidates for more clarity. Romney seemed to be saying that if Dave Camp and Eric Cantor start whipping up votes for a deficit-increasing tax cut for the rich, Romney will issue a veto threat at which point presumably House conservatives will drop the matter rather than pick a doomed fight with a same-party president. Then he and congress will negotiate a revenue-neutral reform with contours TBD. But is that really what would happen? It certainly doesn't sound like the kind of thing that would happen. A Republican president vetoing tax cuts would be a remarkable turnaround from the past several decades worth of American political history. Things can change, of course. And presidents sometimes do pick fights with their base. But what Romney was saying last night is really a dramatic departure from what you'd expect to see happen. This idea should really get aired out.
He should be asked clearly if that's what he's saying and we should hear the reaction from conservative politicians and advocates and such. For my part, I think it sounds like a fishy claim but I'm open to persuasion. In general, though, this kind of way of talking about things—what won't you do, rather than what will you do—makes a lot of sense as way for presidents to talk about their agenda.