One striking aspect of the Capitol Hill putsch was that none of the rioters’ grievances had any basis in reality.

No, the election wasn’t stolen — there is no evidence of significant electoral fraud. No, Democrats aren’t part of a satanic pedophile conspiracy. No, they aren’t radical Marxists — even the party’s progressive wing would be considered only moderately left of center in any other Western democracy.

So all the rage is based on lies. But what’s almost as striking as the fantasies of the rioters is how few leading Republicans have been willing, despite the violence and desecration, to tell the MAGA mob that their conspiracy theories are false.

Bear in mind that Kevin McCarthy, the House minority leader, and two-thirds of his colleagues voted against accepting the Electoral College results even after the riot. (McCarthy then shamelessly decried “division,” saying that “we must call on our better angels.”)

Or consider the behavior of leading Republicans who aren’t usually considered extremists. On Sunday Senator Rob Portman declared that we need to “restore confidence in the integrity of our electoral system.” Portman isn’t stupid; he has to know that the only reason so many people doubt the election results is that members of his party deliberately fomented that doubt. But he’s still keeping up the pretense.

And the cynicism and cowardice of leading Republicans is, I would argue, the most important cause of the nightmare now enveloping our nation.

Of course we need to understand the motives of our homegrown enemies of democracy. In general, political scientists find — not surprisingly, given America’s history — that racial antagonism is the best predictor of willingness to countenance political violence. Anecdotally, personal frustrations — often involving social interactions, not “economic anxiety” — also seem to drive many extremists.

But neither racism nor widespread attraction to conspiracy theories is new in our political life. The worldview described in Richard Hofstadter’s classic 1964 essay “The Paranoid Style in American Politics” is barely distinguishable from QAnon beliefs today.

So there’s only so much to be gained from interviewing red-hatted guys in diners; there have always been people like that. If there are or seem to be more such people than in the past, it probably has less to do with intensified grievances than with outside encouragement.

For the big thing that has changed since Hofstadter wrote is that one of our major political parties has become willing to tolerate and, indeed, feed right-wing political paranoia.

This coddling of the crazies was, at first, almost entirely cynical. When the G.O.P. began moving right in the 1970s its true agenda was mainly economic — what its leaders wanted, above all, were business deregulation and tax cuts for the rich. But the party needed more than plutocracy to win elections, so it began courting working-class whites with what amounted to thinly disguised racist appeals.

Not incidentally, white supremacy has always been sustained in large part through voter suppression. So it shouldn’t be surprising to see right-wingers howling about a rigged election — after all, rigging elections is what their side is accustomed to doing. And it’s not clear to what extent they actually believe that this election was rigged, as opposed to being enraged that this time the usual vote-rigging didn’t work.

But it’s not just about race. Since Ronald Reagan, the G.O.P. has been closely tied to the hard-line Christian right. Anyone shocked by the prevalence of insane conspiracy theories in 2020 should look back to “The New World Order,” published by Reagan ally Pat Robertson in 1991, which saw America menaced by an international cabal of Jewish bankers, Freemasons and occultists. Or they should check out a 1994 video promoted by Jerry Falwell Sr. called “The Clinton Chronicles,” which portrayed Bill Clinton as a drug smuggler and serial killer.

So what has changed since then? For a long time Republican elites imagined that they could exploit racism and conspiracy theorizing while remaining focused on a plutocratic agenda. But with the rise first of the Tea Party, then of Donald Trump, the cynics found that the crazies were actually in control, and that they wanted to destroy democracy, not cut tax rates on capital gains.

And Republican elites have, with few exceptions, accepted their new subservient status.

You might have hoped that a significant number of sane Republican politicians would finally say that enough is enough, and break with their extremist allies. But Trump’s party didn’t balk at his corruption and abuse of power; it stood by him when he refused to accept electoral defeat; and some of its members are responding to a violent attack on Congress by complaining about their loss of Twitter followers.

And there’s no reason to believe that the atrocities yet to come — for there will be more atrocities — will make a difference. The G.O.P. has reached the culmination of its long journey away from democracy, and it’s hard to see how it can ever be redeemed.

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