This is a text I received from a prominent conservative Christian minutes after President Biden’s Inaugural Address: “I broke down sobbing. It’s been a long five-and-a-half years.”

Shortly after that, Scott Dudley, senior pastor at Bellevue Presbyterian Church in Bellevue, Wash., emailed me a note that said, “I never thought I would be moved to tears watching a Democratic president get sworn in, but I was. It just felt so good to hear someone who understands and loves this country and constitution, and is an honorable person, take the oath. I’m praying for healing.”

I’ve had conversations with others who tell similar stories.

Joe Biden is an admirable human being, empathetic and generous in spirit, and his speech was elegant and uplifting. But the tears had to do with something else: We had just emerged from a national trauma. It was only two weeks earlier that the Capitol, on whose steps Mr. Biden took the oath of office, was under assault from a mob that had been incited by his predecessor, Donald Trump, in order to undo an election Mr. Trump lost.

Several people died, including a police officer beaten with a fire extinguisher, and many more easily could have, including the former vice president, Mike Pence. And President Biden’s inauguration came only one day after we crossed an almost unimaginably gruesome milestone: 400,000 deaths from Covid-19, a significant number of which would have been prevented had any of Mr. Trump’s most immediate predecessors, Republican or Democratic, been president instead.

But Mr. Trump’s wounding of America doesn’t end there.

Our economy is crippled, with Mr. Trump ending his presidency with the worst jobs record in modern U.S. history. Americans are angrier, more fearful, less trusting of one another and more polarized than at any time in generations and perhaps since the 1850s. Families, friendships, churches and communities are being ripped apart by the savagery of our politics.

The United States is in the grips of an epistemic crisis, with much of the nation having detached itself from reality. In the eyes of the world, among allies and adversaries, America under Mr. Trump became a joke. So it made sense that once Mr. Trump left the White House, powerful emotions would be unleashed.

I wasn’t immune. In the aftermath of the siege of the Capitol, I found myself angry, which is a rare state of mind for me — angry, not just at Mr. Trump but at his Republican enablers, weak and complicit, some of whom broke with Mr. Trump only when his power was rapidly slipping away. Some had to have seen what was coming; others should have seen what was coming and yet they went along for the ride. So the moment Mr. Biden became president I felt like one door shut and another opened. I wanted to be done with Mr. Trump. But I was convinced that before doing so, I needed to struggle one last time with understanding how things went so terribly wrong.

It’s a complicated story, one we don’t fully understand yet and probably won’t for years. But several factors converged to create this American carnage. The first and most obvious is the radicalized base of the Republican Party. The party has long been a mix of conservatism and populism, but over the years it has became less traditionally conservative, at least in the way Edmund Burke, James Madison and Michael Oakeshott have understood conservatism. The base became increasingly reactionary and populist, anti-elite and anti-establishment, disdainful of science and reason, consumed by grievances and fear.

Among the things that characterized Republican primary voters — not all of them, but large swaths of them — was rage at politicians. This was combined with the belief that the system was rigged against them and that America, to become great again, needed someone in office who would operate outside the usual boundaries. The prevailing attitude was that you had to destroy the village in order to save it. Governing experience was viewed with suspicion, evidence that one had been enlisted in the “deep state.” Civility and compromise were seen as weakness; “owning the libs” was the name of the game. These feelings were amplified in a right-wing ecosystem that thrived off creating conflict and creating enemies. Politics had become too boring; things needed to be livened up.

Enter Donald J. Trump — demagogue, con man, reality television star. A man without any governing experience, Mr. Trump was almost proudly ignorant on policy matters. But what he did know how to do, with frightening success, was inflame the passions of the Republican base, to play to their fears and resentments, especially their racial and ethnic resentments, to turn them against our institutions and constitutional order, and to feed them lies and conspiracy theories.

It began in 2011, when Mr. Trump peddled the racist lie that President Barack Obama was born in Kenya and therefore an illegitimate president, and he just kept going. To his supporters, Mr. Trump was able to turn his vices into virtues, his corruptions into selling points, his cruelty into a synonym for strength. He was willing to bring a gun to a political and cultural knife fight. And while Mr. Trump did many things poorly, he did one thing superbly: conduct an “information-warfare campaign” that spread misinformation and disinformation on a mass scale, which not only promulgated lies but disoriented the public.

All of this is well-known and yet as Mr. Trump retreats in defeat to Florida, a lawless president who was impeached for a second time, it bears repeating: A party that once stood for order, tradition and morality embraced as its leader a man who was transgressive, who embodied disorder, indecency and a “might makes right” ethic. But the most dangerous and unsettling thing about President Donald Trump was his sociopathic tendencies. It should have been obvious to everyone that Mr. Trump was unstable, impulsive, compulsively dishonest and staggeringly narcissistic. The idea that such a person could be controlled and contained, tamed and calmed, was always a pipe dream. No one was going to change Mr. Trump; if anything, it was he who would change them — and that’s exactly what happened.

Add to all that a third, decisive factor that created this American carnage: Republican lawmakers and the political machinery of the Republican Party that empowered Mr. Trump from the opening minutes to the final hours of his presidency. It’s notable that a lot of Republicans in Congress, particularly the Senate, were never comfortable with Mr. Trump. They hoped he would lose the primary in 2016. The attitude was ABT — Anyone But Trump. Republican primary voters had a different opinion, however, and their will prevailed. The size and ease of Mr. Trump’s victory — by the fall of 2015 he was leading the other candidates in the polls and he never looked back — should have been a bigger warning sign than it was at the time.

This led to a growing accommodation between the Republican political establishment and Mr. Trump. It went through various phases, starting with wishful thinking, the hope that Mr. Trump would become more responsible once he won the nomination (nope) — or that once he won the presidency, he would “grow in office.”

When that didn’t happen either, Plan B (or was it Plan C?) was to surround Mr. Trump with responsible people within his administration and in Congress to act as a check on his worst impulses. In some cases, that undoubtedly worked, but not nearly as well as those who hoped to keep Mr. Trump in line had hoped. One prominent Republican who has served in Congress told me recently, “Trump sunk much lower than I thought he would.”

But Mr. Trump, psychologically damaged and morally corrupt, was always going to lead Republicans down darker and darker alleyways. It would only get worse. Yet those who instinctively recoiled at what Mr. Trump was doing decided to go along. For some, it was fear of being criticized by Mr. Trump and his army. They were afraid that speaking out against Mr. Trump would lead to a primary challenge. (The concern was a valid one; they saw what happened to Jeff Flake, Bob Corker and Mark Sanford.)

Some Republicans rationalized their accommodation on the totally unreasonable hope that Mr. Trump — in his 70s, surrounded by sycophants and in possession of unmatched power — would change the habits of a lifetime. Still others convinced themselves they would tolerate what Mr. Trump did just one more time but never again. And yet as Mr. Trump transgressed one ethical line and then another and then another, Republicans continued to justify their silence, their support, or both.

Others believed that since Mr. Trump was president they might as well work with him to get things done in what they perceived as the public interest: judicial appointments, tax cuts, deregulation and the like. In pushing for this, a few individuals, to their credit, never defended Mr. Trump’s indefensible behavior. But far too many did. White evangelicals like Robert Jeffress, Franklin Graham, Jerry Falwell, Jr. and Eric Metaxas were among the worst offenders.

For other Republicans, vaulting political ambition and cynical calculation were at play. Lawmakers like Senator Ted Cruz of Texas, whose wife and father were viciously targeted by Mr. Trump during the 2016 primary campaign, became lap dogs, hoping to receive Mr. Trump’s blessing and win the loyalty of his supporters. Senator Josh Hawley acted so disgracefully in objecting to approval of the Electoral College votes and feeding baseless conspiracy theories that his mentor, John Danforth, said that “trying so hard” to get Mr. Hawley elected to the Senate “was the worst mistake I ever made in my life.” Lindsey Graham proved to be one of T.S. Eliot’s “hollow men,” empty of heart, a person without a moral compass. House Republicans like Matt Gaetz, Jim Jordan, Louie Gohmert, Paul Gosar and Mo Brooks showed themselves to be both carnival barkers and cultlike in their devotion to Mr. Trump.

President Donald Trump leaves office with a crimson-stained legacy; a similar stain attaches to those in the party who supported and sustained him, many of them still in positions of power. Both will move on — Mr. Trump to Mar-a-Lago, disgraced, isolated and politically radioactive, more likely to split his party than ever to lead it again; and the Republican Party facing deep internal division, a massive rebuilding and rebranding effort and a very uncertain future.

President Biden inherits a nation sicker, weaker, angrier, more divided and more violent than it has been in living memory. But if we’re fortunate and wise, we will allow the traumatizing effects of the Trump years to catalyze a rededication to ideals we once cherished in public life but cast aside during the Trump era: honor and integrity, compassion and decency, and old-fashioned competence. America is fragmented but also chastened, perhaps ready to rise again. If it does, when it does, it will be after too many tears have been shed and too many hearts have been broken.

Peter Wehner, a senior fellow at the Ethics and Public Policy Center who served in the Reagan, George H.W. Bush and George W. Bush administrations, is a contributing opinion writer and the author of The Death of Politics: How to Heal Our Frayed Republic After Trump.

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