[Michael Kazin is co-editor of Dissent and a professor of history at Georgetown University. He is completing a history of the American left to be published in 2011 by Knopf.]

John Judis has always been a shrewd reader of election returns. In “You’ve Got Them All Wrong, Mr. President,” his deconstruction of “independent” voters makes clear how meaningless it is for President Obama or anyone else to credit such a huge clump of undifferentiated leaners with the power to decide who runs Congress or gets to sit in the Oval Office. As Judis shows, the only true independents are white working-class men and women (actually, more the latter than the former) who “are susceptible to populist appeals” against “special interests” that “can include business as well as government.”

But, like many a political reporter, Judis focuses more on the messages politicians send out than on the factors that determine how these messages are received. His observations could use a bit less rhetoric and a bit more sociology. Specifically, he neglects one of the main reasons white Americans who lack a college education and make only a modest income now tilt toward Republicans and their right-wing populist talk: Few belong to an institution that counters those opinions....