If you don’t think ideological perceptions matter in American politics, you need read no further. If you do and you’re a Democrat, there’s something to worry about. Even as the terms of the political debate in Washington, in the eyes of many Democrats, have moved steadily to the right, the electorate is increasingly likely to see itself as ideologically closer to the Republican Party than to Democrats. Unless Obama and Democrats can find a solution to this riddle—and find one fast—they will be contesting the 2012 election on forbidding terrain.In mid-2005, as disaffection with the Bush administration and the...