Republican senators were unmoved by former national security adviser John Bolton’s leaked book manuscript on Monday — telling reporters it would not jolt them into voting for impeachment witnesses.

Bolton claims in his upcoming memoir that President Trump in August told him he wanted to freeze $391 million in security assistance until officials in Ukraine helped with his probe into the Bidens, according to a New York Times report.

Appearing vindicated, House impeachment managers said the report proved their claims — but GOP senators quickly deflated hopes they would subpoena Bolton to testify in Trump’s impeachment trial.

Democrats need just four Republicans to break with their party and vote with them to call witnesses and key documents.

“It doesn’t change the underlying facts,” Sen. Ted Cruz (R-Texas) said Monday morning, claiming Trump had the “full authority” to investigate serious allegations of corruption.

“I predicted at the outset of this proceeding that there would be breathless revelations day after day that would be turned into a frenzy. That has been the pattern for some time so I don’t think it’s surprising,” he continued.

Sen. Thom Thillis (R-NC) said Bolton’s testimony hadn’t swayed his vote for witnesses, and seemed to blame reporters for fixating on the contents of Bolton’s upcoming tell-all tome.

“I think you should spend a little bit more time on what you heard on Saturday and check back,” Tillis said, referring to the opening remarks from the president’s legal team.

Other Republican senators including Jim Inhofe of Oklahoma called into question the motivations of the ex-White House aide, speculating he had an ax to grind after he was ousted by Trump in September.

“You have to keep in mind, for the first time in his life he was fired. That does have an effect on people,” Inhofe said.

But some lawmakers signaled they would be open to hearing from witnesses — including key Trump ally Sen. Lindsey Graham of South Carolina.

“If there is a desire and decision by the Senate to call Democratic witnesses, then at a minimum the Senate should allow President @realDonaldTrump to call all relevant witnesses he has requested,” Graham tweeted.

Republicans such as Cruz have floated the idea of “witness reciprocity,” a deal that would allow both House impeachment managers and White House counsel to call their own witnesses.

Moderate GOP Sens. Susan Collins of Maine and Mitt Romney of Utah — who are considered key votes — on Monday confirmed conversations had taken place since the Times article was published Sunday night.

“The reports about John Bolton’s book strengthen the case for witnesses and have prompted a number of conversations among my colleagues,” Collins said in a statement.

Romney also told reporters it was “increasingly likely” there would be enough Republican senators to vote with Democrats to call witnesses.

“I think with the story that came out yesterday it’s increasingly apparent that it would be important to hear from John Bolton,” Romney said, suggesting some colleagues felt the same.

“I think it’s increasingly likely that other Republicans will join those of us who think we should hear from John Bolton,” he added. “I’ve spoken with others who’ve opined upon this as well.”

At a Monday morning press conference, Senate Minority Leader Chuck Schumer (D-NY) said Bolton’s testimony went “right to the heart of the charges against the president.”