There were many foreshadowings of Wednesday’s desecration of the Capitol, but surely one of the clearest came a day earlier, when Mitt Romney was accosted before and during a flight to Washington.

Romney, the Utah senator and former governor of Massachusetts, was minding his own business, waiting to board the flight in Salt Lake City, when people who took offense at his refusal to acquiesce to President Trump’s outlandish attempt to disenfranchise 81 million Americans confronted him.

People began filming Romney with their cellphones, insulting him, telling him he was “a joke, an absolute joke,’’ for daring to disagree with the president. Once on board, likeminded passengers, all no doubt self-styled patriots, taunted Romney, chanting “Traitor, traitor, traitor!’’

What kind of person would behave in such a way?

A few hours later, as an angry mob gathered to listen to Trump dismiss a free and fair election as fraud, the answer was obvious.

With some who taunted Romney presumably among them, the rabble set off for the Capitol to attempt a putsch after their hero, the president, not to mention his son and lawyer, weaponized them with fighting words.

As Romney was the only Republican willing to vote to convict the president of high crimes and misdemeanors last February, it was little surprise he was the most outspoken and prominent Republican to call Trump’s attempt to undermine democracy and overturn the election what it was.

“Has ambition so eclipsed principle?’’ Romney asked last week. It was, essentially, an updated version of the question Army lawyer Joe Welch posed to Senator Joseph McCarthy, a political precursor to Trump, in 1954: “Have you no sense of decency, sir, at long last? Have you left no sense of decency?’’

But Romney’s rhetorical question was aimed not just at his president but at his Republican colleagues who have humored and enabled Trump in his delusions.

Such honesty, dismissed by some as opportunism, invited the kind of unhinged venom unleashed on that airplane.

Romney could have kept his mouth shut. Last February and last week. But he didn’t. He dared to say that the emperor, the most popular member of his own party, someone who garnered 74 million votes, was naked — cloaked, that is, in nothing but his savage narcissism and will to power.

For this, history will judge Mitt Romney among the righteous and judge Donald Trump the worst, and least honorable, president ever.

There are multiple reasons why some people, among them many from Massachusetts, will never like Romney. As governor, he basically checked out after a couple of years to focus on running for president, trashing his own state in the process. He is prone to flip-flopping, changing his positions to fit whatever office he is pursuing and whichever audience he is addressing.

And he had his moments of weakness in the face of Trump. His willingness to prostrate himself before then President-elect Trump, someone whom only months before he dismissed as a con man, to seek a cabinet position was cringe-worthy and ultimately humiliating.

But that’s just politics. And if politics ain’t beanbag, it ain’t everything, either.

Yet inside Romney’s humiliating and inevitably futile quest to become Trump’s Secretary of State rests some of the most telling features of his character. He refused Trump’s command to apologize for his previous criticisms as a quid pro quo for joining the administration. And while it is true he was humiliated, in order to be humiliated, you must possess a sense of humility.

Romney is the rarest of politician in that he is not afraid to call out members of his own party, including the leader of his own party. That’s got to count for something.

And he has done it, repeatedly, knowing it would attract the kind of abuse he endured at the airport and on that flight. That assault on his character will not be the last he endures.

His courage, his utter decency, however opportunistic it can sometimes seem, stands in such stark relief to Trump and his enablers.

When the Senate resumed its duties Wednesday night, in a building still strewn with broken glass and broken covenants, Romney rose and, unlike his Republican colleagues, lay the blame for the day’s disgrace squarely at the feet of the smallest of presidents.

“What happened here today was an insurrection, incited by the president of the United States,’’ he said.

Romney chastised his Republican colleagues who, even in the wake of such unprecedented, shocking violence fueled by lies and conspiracy theories, continued to do Trump’s bidding. He begged them to stop feeding the mob.

“Please!’’ Romney said. “No congressional-led audit will ever convince those voters, particularly when the president will continue to claim that the election was stolen. The best way we can show respect for the voters who are upset is by telling them the truth.’’

Romney’s words were greeted with sustained applause.

From Democrats.

Those same Democrats may be in a position one day to help Romney politically, maybe vote in favor of something he holds dear. So beyond doing the right thing, Romney may have done the politically wise thing.

He belies the idea that bipartisanship is dead and gone forever, in the grave with congressional decorum. In the currency favored in Washington, Democrats now owe him.

It has always been amusing to listen to politicians in Washington, both the God-fearing and the godless, invoke religion so regularly, because the only deity truly worshiped there is power.

But anyone who has spent any appreciable time around Romney knows that he takes his faith very seriously. It informs who he is as a politician and, especially, as a person. He believes he will be judged after this life, and acts accordingly.

Trump behaves as someone who is accountable to no one, and certainly to no higher power. He has trashed every norm that restrained his 44 predecessors. Beyond the balance of powers enshrined in the Constitution, presidents historically have been held in check by the knowledge that history would judge them.

But, by word and deed, Trump has demonstrated that he does not care what historians write. He believes in nothing but himself. He has zero empathy, zero spirituality. He values no judgment but his own.

Mitt Romney’s decency is rooted in the basic fact he knows, he believes, that for all the trappings of wealth and power he has enjoyed, one day, on the day he takes his last breath, all that won’t matter a whit.

That belief defines humility — something rare, and something utterly necessary now, as the broken glass is swept up and the world bids goodbye, at last, to Donald J. Trump.

Kevin Cullen is a Globe columnist. He can be reached at kevin.cullen@globe.com.