We are not going to make any progress on our biggest problems without a compromise between the center-right and center-left. But, for that, we need the center-right conservatives, not the radicals, to be running the G.O.P., as well as the center-left in the Democratic Party. Over the course of his presidency, Obama has proposed center-left solutions to all four of these challenges. I wish he had pushed some in a bigger, consistent, more daring and more forceful manner — and made them the centerpiece of his campaign. Nevertheless, if the G.O.P. were in a different place, either a second-term Obama or a first-term Romney would have a real chance at making progress on all four. As things stand now, though, there is little hope this campaign will give the winner any basis for governing. Too bad — a presidential campaign is a terrible thing to waste.