Looking over the reactions of last night's debate like the political crack-monkey that I am, I was struck by the number of left leaning commentators who took the line, "Yeah, Romney seemed to win the debate, but he only got away with it because he was so vague and slippery. How could people support a president who doesn't have a detailed plan for [taxes / health care / reforming entitlements, etc.]?"
One of the things that people seem to forget constantly, given the over-emphasis on presidential politics above all others, is that the president does not have the power to write legislation. Obama repeatedly talked about his "detailed" plan for dealing with the deficit. However, given that Obama hasn't even been able to get a budget passed for the past three years, it's a little hard to believe that his long term plan for dealing with the deficit and taxes matters. All the president gets to do is urge congress to pass something that he's willing to sign, and then decide whether to sign or veto what hits his desk.
Presidents can talk all day about their detailed plans (and at times during the debate it seemed like Obama was going to try to do exactly that, with responses that managed to meander from health care to foreign policy and back to taxes without ever actually reaching a point) but at the end of the day they don't write legislation. Their leadership is important: clearly, it was in part Obama's decision to devote much of his first two years to "ObamaCare" rather than more specifically to economic policy, even though he was at the mercy of the Democratic congress in regards to what actually ended up in the bill. But presidents do not have the power to pass legislation. In this regard, the sort of vague principles that Romney was sticking to are fine for someone running for the chief executive position in the government. We got a pretty good idea what sort of bills Romney would likely sign or veto, and that's all that he would get to do.