Former U.S. Sen. John C. Danforth saw a mob of rioters take over the Senate chamber where he had spent much of his professional life. The dean of the Missouri Republican Party was a member of the Senate between 1976 and 1995.

“That place,” he said of the Senate, “is very familiar to me. To see it under attack was awful. It was unimaginable.”

Like the rest of the world, Danforth was shocked as rioters — some waving Confederate flags, all of them supporters of President Donald Trump who believed his lies that the election had been stolen from him — laid siege to the U.S. Capitol, stopping Congress in its tracks as it performed the generally pro forma process of recording the state-by-state Electoral College votes.

The process was anything but normal this year, however, because Sen. Josh Hawley, the junior senator from Missouri, followed by other senators and dozens of House members, decided to object to approval of the votes in a move that fed baseless conspiracy theories that the election was rigged. Before the insurrection against the Capitol, after Hawley, a Republican, had become the first senator to announce plans to seek to overturn the election of President-elect Joe Biden, Danforth criticized his protégé, a fellow Yale Law School graduate.

He called Hawley’s plan “radical” and dangerous.

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Now, after the attack on the American election and the siege by rioters that left four people dead, Danforth has even stronger words.

Supporting Josh and trying so hard to get him elected to the Senate was the worst mistake I ever made in my life,” Danforth said in a phone interview Thursday afternoon. “Yesterday was the physical culmination of the long attempt (by Hawley and others) to foment a lack of public confidence in our democratic system. It is very dangerous to America to continue pushing this idea that government doesn’t work and that voting was fraudulent.”

It’s not just Hawley who has been stoking this false sense of populism, but a long series of Republicans, from Kris Kobach of Kansas, to dozens of Republicans in the Missouri Legislature, and, of course, for the past four years, Trump. Danforth was one of the first national Republicans to openly criticize Trump’s extremism and stoking of conspiracy theories. Now, after the insurrection, he’s hoping Wednesday’s events are a turning point, not just for his party, but the nation.

“I hope at least it was a catharsis,” Danforth says, “that this is a time to reflect as a country what has gone wrong, all of us, left and right, but particularly in my Republican Party.”

Some of that healing, perhaps, happened back on the Senate floor Wednesday night after the Capitol had been cleared, when Sen. Mitt Romney, R-Utah, the only Republican to have voted to convict Trump in his impeachment trial, made it clear how Republicans should be responding when their constituents espouse conspiracy theories.

“Tell them the truth,” Romney said.

Indeed, Danforth had a similar thought a week or so ago, when in a hearing, Hawley tried to justify his plan to object to the Democratic election of Biden because on a phone call with constituents, nearly all of them had questioned the results of the election.

“My thought when he said that was: ‘Josh, what did you say in response? Did you push back at all?’” Danforth recalls.

Of course, Hawley didn’t. He won’t tell the conspiracy theorists the truth, because he’d rather stoke their fears so they will send him money for a future presidential race.

This is dangerous, Danforth says, and the whole nation saw what happens when an entire political party — his party — doesn’t do enough to stop it. The Republican Party must disentangle itself from the deal it made with the devil in backing Trump, Danforth says, or it will never win national elections again.

Danforth once viewed Hawley as a “special talent” who would bring keen intellect to the chamber. Now he’s disgraced the institution, Danforth says, and he regrets that he ever supported him.

“This guy,” he says of Hawley, “is doing real harm. What he’s doing to his party is one thing. What he’s doing to the country is much worse.”