Four years after a presidential election that looked, briefly, as if it might put an end to America's partisan warfare, we find ourselves further embroiled in it, as reports from the run-up to the Iowa caucuses reminded us almost daily. Only now what once seemed disagreements over solutions have grown, or deteriorated, into profound differences over just what the problems are. This was not the case a generation ago, when the two major parties found common ground on some of the most pressing issues of the day - as Geoffrey Kabaservice points out in "Rule and Ruin. The Downfall of Moderation and the Destruction of the Republican Party: From Eisenhower to the Tea Party," one of two books reviewed by Timothy Noah on this week's cover. While the Tea Partiers, at odds with anyone they suspect belongs to an out-of-touch establishment, have little use for moderation, they do regard themselves as the authentic voice of what used to be called "Middle America," at least to judge from "The Tea Party and the Remaking of Republican Conservatism," Theda Skocpol and Vanessa Williamson's survey of the movement, also reviewed by Noah. And what of the American left, and the new insurgency known as Occupy Wall Street? Its participants too are troubled by the state of our politics, in particular the misalliance of money and power. This is the case made in the third book reviewed on our cover, Thomas Frank's "Pity the Billionaire: The Hard-Times Swindle and the Unlikely Comeback of the Right." The reviewer is Michael Kinsley.