However the budget showdown ends—and, as I write this at lunchtime on Monday, a temporary government shutdown is looking like the most likely outcome—its defining moment came on Saturday, when House Republicans decided to demand a one-year delay in Obamacare as the price of funding the government beyond September 30th. At a closed-door meeting of the Republican caucus, cheers erupted when Speaker Boehner announced the plan. The whole room shouted, “Let’s vote!,” according to John Culberson, a Texan hard-liner. “And I said,” he recalled, “you know, like 9/11: ‘Let’s roll.’ ”

Really, what can you say about that? An elected representative comparing a political protest against a piece of legislation that the President twice ran upon, that Congress voted through, and that the Supreme Court upheld, with the desperate rallying cry of a passenger, Todd Beamer, trapped aboard a jetliner that had been hijacked by Al Qaeda terrorists.

Like many other people, I’m sure, I spent the weekend talking to friends and relatives about what’s happening in Washington. But when asked what was going to happen, about the only thing I could think of to say was “I don’t know.” Like most other pundits, I had assumed that the G.O.P. would cause a big stink and then, at the last moment, its leadership, fearful of the electoral consequences of following a path that even a large majority of Republican voters oppose, would buckle. That could still happen. As the midnight deadline approaches, there will surely be at least one more round of back-and-forth between the House and the Senate. But what the past few days have demonstrated is that there is a significant minority within the Republican Party, both on Capitol Hill and at its grass roots, that would have preferred to stick with the suicide option to the bitter end.

How to describe this faction, which is, by far, the most energetic group in the G.O.P.? Three years after the Tea Party’s coming-of-age party in the 2010 midterms, it’s still a tricky question. Last week, in writing a guide to the budget crisis, I used the term “Poujadists,” comparing the Republican right to the provincial French shopkeepers and artisans who backed the populist Pierre Poujade during the nineteen-fifties. But when, at a family party, I ran into Jerrold Seigel, a professor emeritus at N.Y.U. who specializes in French history (and who is my wife’s uncle by marriage), he pointed out that the Poujadists, while animated by some of the same concerns as conservative Republicans, such as high taxes and resentment of what they saw as a corrupt metropolitan élite, lacked the acute anti-government animus that motivates the American right. We need some new language to describe their Republican counterparts, Seigel said, because none of the historical parallels are exact.

That’s surely true. One precursor is the agrarian populist movement, which spread throughout the American heartland like prairie brush during the Gilded Age of the late nineteenth century. The populists, like the Tea Party supporters, were motivated by a feeling that rapid economic and demographic change was destroying the true America, as represented by honest farmers. They were partial to conspiracy theories of various descriptions, and, despite some early efforts to reach out to freed blacks, their movement was tinged by racism and white supremacism.

Clearly there are some parallels between the populists and the self-styled “patriots” of today. But there are also important differences. In economic terms, populism was a left-wing movement dedicated to undoing some of the vast inequities that rapid development and industrialization had begotten. “On the one side stand the corporate interests of the United States, the moneyed interests, aggregated wealth and capital, imperious, arrogant, compassionless,” William Jennings Bryan, a.k.a. the Great Commoner, declared in a famous speech. “On the other side stand an unnumbered throng, those who gave to the Democratic Party a name and for whom it has assumed to speak.” The Tea Party sometimes rails against Wall Street, but is hardly a movement of the downtrodden masses. According to opinion pollsters that have probed its makeup, its members are richer and more educated than the median American. Tea Party supporters are mostly men, overwhelmingly white, and about half of them are of retirement age.

It is dangerous to generalize, but American conservatism, at its base, seems to be primarily a movement of a middle class that sees itself as squeezed, besieged, and neglected, and whose grievances have as much to do with values as economics. In this, it shares something with earlier right-wing movements, such as the John Birch Society, and, demographically at least, with the radical right-wing movements of interwar Europe. That’s not to say it’s a fascist movement by any means. The European fascists were big-government conservatives, not small-government conservatives; they lacked the religious fundamentalism that motivates many American right-wingers; and, in some countries, they subscribed to a poisonous brew of racism, anti-Semitism, and eugenics that went well beyond the instinctive white-on-black racism that has long tinged American conservatism.

Still, there are some worrying parallels. Like their forebears in places like France, Italy, and Germany, a good number of American conservatives sincerely believe that their government has ignored their wishes and betrayed not just them but the very notion of Americanness. History suggests this is a dangerous road to go down. Once an elected government is deemed illegitimate, in whatever sense, normal democratic politics, with its give and take, is difficult to sustain. And that, of course, is what we are now witnessing. On parts of the right, policies on issues such as immigration, gun control, and health-care reform are no longer viewed on their individual merits. They are all part of a Manichean struggle over the future of America. And with the first non-white President nine months into his second term, at least some G.O.P. activists and media incendiaries have infused the fight with a very personal and vindictive tone. (To be fair, liberals had a similar antipathy toward George W. Bush.)

It is only in this context that the animus, language, and antics of the G.O.P. can be understood. Does Ted Cruz, an articulate Canadian-born graduate of Harvard Law School, really believe that Obamacare, which started out at the Heritage Foundation twenty years ago as a conservative alternative to Hillarycare, is a socialistic scheme that will destroy the American economy? Of course he doesn’t. But he knows that describing it as such, and threatening to shut down the U.S. government, will play to the base and further his own ambitions.

Does Culberson, who represents a Houston district that is one of the wealthiest in the state of Texas, really think that the struggle against Obamacare is comparable to fighting terrorists with your bare hands? I presume he doesn’t, but in his case it’s hard to be sure. An ardent fiscal and social conservative, in 2009, when the conspiracy theories about President Obama’s place of birth were at their height, he co-sponsored a bill in Congress to require Presidential candidates to publish their birth certificates. Perhaps Culberson simply got carried away on Saturday and used some language he later regretted. But that, apparently, isn’t the case. On his Twitter account on Saturday, he said, “As usual the press misquoted me - I said since we Rs are in 100% agreement, let’s roll. One of my favorite expressions.” Later, in another tweet, he added, “Todd Beamer is one of my heroes - they voted for a course of action, all agreed and he said let’s roll. A great expression, period.”