On Thursday afternoon, in a New York courtroom, Donald Trump wore a glum look on his face as a jury pronounced him guilty of 34 felony counts of falsifying business records, sitting slack as he became the first former president to ever be convicted of a crime.

Then he marched up to the cameras in the hallway to claim, falsely, that it was all a setup.

“Our whole country is being rigged right now,” Trump said. “This is being done by the Biden administration in order to wound or hurt a political opponent.”

That isn’t true. Trump’s trial in New York is a local matter that was brought by District Attorney Alvin Bragg, and it has nothing to do with President Biden or his administration.

But that didn’t stop Trump and his allies from trying immediately to weaponize it — to wield it in his long effort to undermine trust in the courts, the justice system, and perhaps in the 2024 election itself.

Trump was convicted of falsifying business records as part of a scheme to cover up a sex scandal that threatened to erupt while he was running for president in 2016. Prosecutors said it was an unlawful effort to influence that election, and Trump has tried to turn that accusation on its head.

For months, he has been deliberate, repetitive and disciplined in the words he uses to talk about the trial. He calls it the “Biden trial.” He calls it “election interference,” as he did earlier Thursday on his social media website. He calls it a “witch hunt.”

On Thursday, his allies quickly joined the chorus. Kari Lake, the Arizona Senate candidate, described the verdict as “the most egregious example of election interference and an outright mockery of the rule of law in the 246-year history of our Republic.”

The Republican speaker of the House, Mike Johnson, called the trial a “purely political exercise, not a legal one,” and accused the Biden administration of participating in “the weaponization of our justice system.”

Trump’s statement immediately after the verdict showed that he will use it to try to erode faith in the system that convicted him. That’s likely to worry Republicans and Democrats alike who are concerned about the future of American democracy, which relies on public trust.

“This was a conviction by a jury of Americans who listened to the evidence and made their decision,” said Rachel Kleinfeld, a senior fellow in the Democracy, Conflict, and Governance Program at the Carnegie Endowment for International Peace. “When you undermine courts the way that elections have already been undermined, there is no peaceful way to settle differences.”

For Trump and his campaign, the party line is grievance, anger and a call for revenge. And one Republican who strayed from it was immediately subject to criticism from one of Trump’s closest aides.

“Regardless of the result, I urge all Americans to respect the verdict and the legal process,” former Gov. Larry Hogan of Maryland, a Republican running for Senate, posted on X shortly before the verdict was announced.

“You just ended your campaign,” Chris LaCivita, a senior adviser to Trump, shot back at Hogan in his own post.

Even a vanilla statement about trusting the verdict and the process, it seemed, was too much for Trump’s team.

REPORTER’S NOTEBOOK

What it was like inside the courtroom

My colleagues Maggie Haberman and Jonah Bromwich have been inside Courtroom 1530 for much of the past eight weeks. It’s a plain space with harsh bright lights. And they were there as Trump learned he had been convicted.

I asked Maggie what that moment was like. “Intense,” she said. “Like time stopped.”

Jonah described the scene this way.

It happened very quickly.

The jury filed into the courtroom and climbed into the jury box. The jurors confirmed that they had reached a verdict. And then the foreman, who had sat silent all trial until today, stood up, took a microphone and was asked what he and 11 other New Yorkers had determined about the first criminal charge against Donald J. Trump.

“Guilty,” the foreman said. The former president shut his eyes, then slowly shook his head.

Read more here.

What to read about Trump’s conviction

Before Trump left the courthouse, Judge Juan Merchan set a date for his sentencing: July 11, four days before the beginning of the Republican National Convention, where he is set to accept the nomination to be his party’s candidate for president.

It’s an extraordinary twist in an extraordinary campaign. Here’s what to know so far.