As the Senate reconvened Thursday for President Trump’s historic impeachment trial, a name began trending on Twitter among those pushing for the president’s removal from office: Fox News senior judicial analyst Andrew Napolitano.

Better known as Judge Napolitano or Judge Nap, the conservative commentator was once a Trump supporter and purveyor of conspiracy theories. But recently, Napolitano has shifted his stance on the president, voicing criticisms of Trump that are often at odds with the views of his fellow Fox News personalities.

Napolitano’s deviation from Fox News’s normally pro-Trump opinion programming continued this week when the former New Jersey Superior Court judge published an opinion piece pushing back against the president’s repeated claims that the impeachment proceeding is a “hoax.”

Napolitano described the proceedings as “deadly serious business based on well-established constitutional norms.” He also made a case for why he believes there is “ample and uncontradicted” evidence for the Senate to vote to remove the president, writing that there are “valid, lawful, constitutional arguments for Trump’s impeachment that he ought to take seriously.”

The op-ed appeared to have been first published Wednesday by the Washington Examiner, a conservative news outlet, before it showed up on Fox News’s site early Thursday.

“What is required for removal of the president?” Napolitano wrote. “A demonstration of presidential commission of high crimes and misdemeanors, of which in Trump’s case the evidence is ample and uncontradicted.”

This is not the first time that Napolitano has pushed for Trump’s impeachment in recent months, nor is his stance all that surprising, given that he has been described as a “staunch libertarian” who “places principles over partisanship, and who is outspoken and critical without resorting to ad hominem attacks.”

But the op-ed, which comes just days before Trump’s defense is expected to present its case Saturday, quickly gained traction on social media Thursday as many, including House Speaker Nancy Pelosi (D-Calif.), Rep. Eric Swalwell (D-Calif.) and Rep. Katherine M. Clark (D-Mass.), shared the piece. By late Thursday, “Judge Napolitano” was a trending term on Twitter with tens of thousands of mentions.

“When Fox News’ top legal analyst debunks the rest of Fox News …” Swalwell tweeted. Clark, who is vice chair of the House Democratic caucus, wrote that Napolitano “acknowledges what we already know: the President abused his power & should be removed from office.”

In his piece, Napolitano detailed the two charges against Trump — abuse of power and obstruction of Congress — and laid out the evidence that, he argues, should support impeachment. Napolitano pointed to internal emails showing that the White House withheld military aid to Ukraine after Trump’s July 25 call with Ukrainian President Volodymyr Zelensky, and senior officials defying congressional subpoenas to testify.

“The Constitution prescribes the bases for impeachment as treason, bribery or other high crimes and misdemeanors,” he wrote. “However, this use of the word ‘crimes’ does not refer to violations of federal criminal statutes. It refers to behavior that is so destructive of the constitutional order that it is the moral equivalent of statutory crimes.”

Napolitano also went after unnamed Republican senators, accusing them of reassuring Trump that he will be acquitted.

“Whoever may have whispered that into his ear is unworthy of sitting as a juror and has violated the oath of ‘impartial justice’ and fidelity to the Constitution and the law,” he wrote.

Napolitano’s op-ed presents a stark contrast to a majority of Fox News’s impeachment coverage, which in recent days has favored disparagement of Democrats and pro-Trump commentary over airing live footage of the proceedings.

“Imagine a movie written and directed by children whose ending you already know, and by the way, it’s 20 hours long and Hungarian with misspelled subtitles,” Fox News host Tucker Carlson said Wednesday, following the first day of opening arguments for Democrats. “That’s what it’s like.”

Later that night, host Sean Hannity, a close Trump ally, adopted a similar take on the day’s events.

“Now, if I was a terrible host, I would force you to endure watching the regurgitation, the repetition … the insanity that has gone on all day, America, 24 hours of never-ending babbling, repetitive talking points over what was nothing,” he said.

On Thursday, Trump critics cited Napolitano’s arguments and praised the Fox News analyst for being “willing to tell the truth” and remaining “true to his principles.”

“The Judge is a courageous man and now he must fight the cabal that wants to keep someone this lawless and reckless in our most sacred public servant position,” tweeted former White House communications director Anthony Scaramucci.

A headline on an article from the Palmer Report, a liberal political blog, read, “Judge Napolitano of Fox News just destroyed Donald Trump’s impeachment defense.”

Not everyone, though, was receptive to the op-ed.

“I change channels when this idiot shows up,” one person wrote in the comments section of the piece. “He belongs at CNN or a nut house. Same difference.”

Another urged the network to find another legal expert, writing, “Nap has been so wrong, so often that I thought Fox finally let him go to pasture.”

Trump has not yet publicly addressed the column. Instead, the president tweeted two clips from Hannity’s show Thursday night, during which the host railed against the “Schumer Schiff Sham Show.”