Fox News senior judicial analyst Andrew Napolitano blasted Republicans on Tuesday for turning on former national security adviser John Bolton, who he said was considered to be “a conservative icon until two days ago.”

In an appearance on Fox Business, Napolitano defended Bolton, who was a regular contributor at the network for 11 years until he took up his White House post in 2018.

“We know John,” Napolitano, a former judge, said. “He used to work here. He’s a very intelligent, strong-willed, meticulously honest person.”

Bolton was “a conservative icon until two days ago,” he went on. “Now the things they’re saying about him, it sounds like they’re talking about Nancy Pelosi. But he has come out with something that goes to the core of the case.”

It was recently reported that an upcoming book by Bolton contains allegations that confirm the main charge against President Donald Trump in his Senate impeachment trial, according to The New York Times, which obtained a copy of Bolton’s manuscript.

His account alleges that the president tied the release of congressionally approved Ukraine aid to that country’s government opening an investigation into former Vice President Joe Biden and his son Hunter. The bombshell accusation has increased pressure on Senate Republicans to call witnesses in the Senate trial, including Bolton, who has said he’s willing to testify.

Dobbs, a Fox Business Network host, attacked Bolton ― who has served in every Republican administration since President Ronald Reagan ― as “a tool for the radical [Democrats] and the deep state.”

Napolitano argued Tuesday that because Trump’s legal team had chosen to argue the facts of the case, instead of simply stating that the charge was not an impeachable offense, Bolton’s account blew a hole in their defense. (He added that, for the record, he does think it was an impeachable offense.)

“Now that this witness at the core of everything who had personal conversations with just the president has come forward with a version 180 degrees from theirs, I think they’re stuck with this,” Napolitano said. “I think many Republicans are now going to say, ‘We have to hear from Bolton.’”

Republicans have repeatedly blocked Democrats’ attempts to allow new evidence in the impeachment trial, squashing pushes for testimony from firsthand witnesses like Bolton. However, some hours after Napolitano’s remarks Tuesday, Senate Majority Leader Mitch McConnell (R-Ky.) reportedly said the GOP does not currently have enough votes to prevent witnesses.