Every four years, the torrent of political books that pours from the presses tells you something about the underlying movement of American politics that campaign coverage usually fails to see. The thematic zeitgeist this year is so basic and longstanding that it could have dominated book publishing four years ago, or eight, or even sixteen: the extremism of the Republican Party and how it’s destroying American politics.

This is the subject of Geoffrey Kabaservice’s thorough historical study, “Rule and Ruin: The Downfall of Moderation and the Destruction of the Republican Party, from Eisenhower to the Tea Party.” It’s the angry complaint of “The Party Is Over: How Republicans Went Crazy, Democrats Became Useless, and the Middle Class Got Shafted,” a memoir-cum-jeremiad to be published in August by Mike Lofgren, a former Republican congressional staffer. It’s the underlying diagnosis that’s not quite made explicit in the title of Thomas E. Mann and Norman J. Ornstein’s new book, “It’s Even Worse Than It Looks: How the American Constitutional System Collided with the New Politics of Extremism.” And it’s the disenchanted theme of “Patriots,” a new novel by the writer David Frum.

That’s an interesting lineup of authors drawn in different ways to the same subject at the same moment. Kabaservice is a young history professor, but the others are, in one way or another, longtime Washington insiders—frogs who have steeped for decades in this particular pot of water and, contrary to the cliché, recognized when it reached a level of intolerability. Lofgren worked for almost thirty years on Capitol Hill. When he arrived, in 1983, he was a moderate Midwesterner looking for short-term employment in government. He found it working for a series of Republican deficit hawks. Back then, there was room in the party for someone like Lofgren, who saw himself above all as a professional congressional staffer with an expertise in defense budgets. For the usual reasons of exigency and inertia—that is, life—he stayed put in his job, while his party and institution deteriorated.

Last year, Lofgren retired in the wake of the Tea Party sweep. Almost immediately, he wrote a devastating essay, “Goodbye to All That,” which described the Republican Party as an “apocalyptic cult” given to lying and delusional thinking in the manner of certain authoritarian political movements of the early twentieth century. (Lofgren did graduate work on German history.) He wrote about how the party took advantage of a profoundly ignorant electorate, an easily conned and distracted media, and a cowed Democratic Party to press the ideological struggle in spite of the deep unpopularity of many of its positions. If all of this had come from a Nation columnist, it would have been unremarkable. Instead, it came from a mild, inconspicuous Hill staffer who hadn’t written a political word in thirty years in Washington. The essay had the feel of a long-repressed confession and the authority of an insider’s testimony, like the anti-war views of a decorated infantry officer. Perhaps the novelty will have worn off by the time the book-length version comes out, but Lofgren’s ideas are trenchant and far-reaching enough to outlast the dog-bites-man quality of the original essay.

Frum is much better known. Most of his earlier books were written from the point of view of a conservative who saw his own side lacking the courage of its convictions. But something changed for Frum in the wake of the Iraq War and other disasters of the Bush Administration, in which he played a small, early role. In 2008, in “Comeback: Conservatism That Can Win Again,” he urged Republicans to embrace less rigid, more centrist positions on the environment, social issues, economics, and other matters as a way back to power. But that book was quickly overtaken by the party’s rabid reaction to its 2008 defeat and Obama’s Presidency. Instead of moving to the sensible middle, it doubled down on its own extremism, both ideologically and as a matter of strategy. Frum entered into a series of scraps—with the radio loudmouths Rush Limbaugh and Mark Levin, and with his own employer, the American Enterprise Institute, which fired him after he published a critique of the Republican strategy in trying to kill health-care reform.

By 2010, Frum had become one of the party’s few high-profile apostates, and its bravest. “Patriots” is a novel about a wealthy young man who wanders into the conservative (“Constitutionalist”) archipelago in a just barely imaginary Washington and allows himself to be used by various operators for their own ends—which turn out to be more mercenary and self-seeking than principled. Frum’s Republican Party, unlike Lofgren’s, looks less like National Socialism in Weimar Germany than something closer to home—the cynicism of the Gilded Age, when élites turned to pillage and plunder while the country oscillated between rebellion and decay.

In a way, Mann and Ornstein are the unlikeliest polemicists of all. For forty years, they have been watching Congress from, respectively, the Brookings Institution and A.E.I. They have been the very voice of the responsible center in Washington, frequent and sober-minded guests on “News Hour,” never tipping their partisan hand, always careful to provide sympathetic criticism of Congress and make modest, helpful suggestions. They have been so close to institutional power and so trusted by politicians of both parties that, back in 1979, a bipartisan group of House freshmen agreed to meet them for periodic dinners and discuss legislation and politics. The group included Dick Cheney, Geraldine Ferraro, and Newt Gingrich. It’s impossible to imagine anything similar happening today.

Those dinners are mentioned in Mann and Ornstein’s new book, not as an emblem of a bygone era of comity, but as the original “seeds of dysfunction.” Much of the blame for what went wrong in Washington goes to Gingrich and his brand of modern, scorched-earth Republicanism. Mann and Ornstein call the phenomenon, rather delicately, “asymmetric polarization.” They’ve come to their conclusions more in sorrow than in anger, with the bona fides of gentlemen who would rather not have to pick sides in a partisan fight: “However awkward it may be for the traditional press and nonpartisan analysts to acknowledge, one of the two major parties, the Republican Party, has become an insurgent outlier—ideologically extreme; contemptuous of the inherited social and economic policy regime; scornful of compromise; unpersuaded by conventional understanding of facts, evidence, and science; and dismissive of the legitimacy of its political opposition.” Like Lofgren, they blame an intellectually lazy or timid media for pretending that the problem lies equally with both sides.

In keeping with their constructive role, Mann and Ornstein make a variety of proposals for “fixing” American politics, ranging from holding elections on weekends to calling out political falsehoods on the front page of newspapers. Their ideas are reasonable and, in a few cases, novel, but they suffer from a problem of circularity: the very élites they call on to provide leadership in cleansing American politics are themselves too compromised, or simply no longer trusted by a jaded public, to play that role. Frum’s novel, which has no burden of constructive suggestions, comes closer to offering a persuasive picture of the political present and the foreseeable future. It’s not a happy one.

None of this should be surprising. Anyone under forty has been living with it throughout their conscious lives, and anyone over fifty has seen its entire trajectory through grownup eyes. What’s striking about these books is where they come from, or from whom, and that they all come at the same time. They arrive in the middle of Romney’s speech on education and Obama’s comments on Bain Capital to remind us of a deeper, more lasting, more important truth about American politics. The outcome of this year’s election won’t change that trajectory.

Illustration by Tom Bachtell.