With their cowardly refusal to discipline Marjorie Taylor Greene, the retreat from integrity of the House Republicans is now complete. Only under the threat of sanctions against Greene by House Democrats did Minority Leader Kevin McCarthy (R-CA) even pretend to address the Georgia representative's many offenses against decency, comity, and sanity. And when the Republican caucus met behind closed doors, McCarthy's weak leadership allowed Greene to take over the meeting, which reportedly concluded in applause for her.

What were the Republicans applauding? The gun-toting Greene has not apologized for any of her endorsements of violence, including those spittle-flecked threats to assassinate House Speaker Nancy Pelosi. She hasn't withdrawn any of her racist slurs against Blacks and Muslims, or her gutter excursions into anti-Semitic fantasy. Only under duress has Greene admitted the reality of the 9/11 attack and the school shootings upon which she had cast paranoid doubt, after inflicting renewed grief on the families of the dead. She didn't apologize to them, either.

Behind closed doors, Greene reportedly told her Republican colleagues that she is sorry for embarrassing them. Her alibi was that she was drawn to QAnon only because she was suffering a "dark period" in her life. Yet that too was a lie. She praised the conspiracy cult on Twitter as recently as December 4.

So this wretched character deserves to be booted off the prestigious budget and education committee assignments that McCarthy had unaccountably awarded her. But with little intellectual aptitude and no interest in policy, she will hardly suffer from that sanction. Instead she now gloats that all the attention to her baneful idiocies is elevating her profile, a boast that is surely accurate. She will bask in attention – and rake in money – from the aggrieved bigots for whom she stands.

There can be no doubt that Greene and others like her pose a continuing threat to democracy, as they proved with bloody ferocity on January 6. In their psychotic fantasies -- as she hinted in her own social media posts -- they would exterminate every Democrat and liberal in America, because "freedom" is only for them and nobody else.

But what these violent extremists are much more likely to destroy is conservatism.

In one of her many defiant public rebukes to her critics, Greene wrote that Pelosi persecutes her because she is "a Christian" and "a conservative." Obviously her brutal style does no credit to Christianity, but it is conservatives who should worry more about her claim to being one of them.

At their best, conservatives are supposed to defend American institutions and values. They are supposed to believe in civility, protocol, manners, and traditional standards. The conservative instinct is to reject excess and uphold personal responsibility. They valued reason and logic over maddening emotion. Or at least those were the things they believed about themselves.

In recent decades, however, that venerable sort of conservatism has increasingly given way to a coarser and uglier version, which is now epitomized by Trump and his followers such as Greene. If she is a conservative, with her crazy theories about a Jewish space laser and her stupid prejudices, then conservatism is intellectually bankrupt and merely a political scrim for fascism.

This was the same danger perceived by William F. Buckley, the framer of modern conservatism, when he sought to isolate the authoritarian and conspiratorial John Birch Society from his movement. With its wild accusations against Dwight Eisenhower and its hatred of democracy, he knew that the society would poison conservatism in its cradle.

Some Republicans, notably including Senate Minority Leader Mitch McConnell and a handful of Senators and Representatives, seem to recognize this peril. The question is whether they have the courage and energy for a sustained fight against it.