Want the best of VICE News straight to your inbox? Sign up here.

WASHINGTON — Sen. Ted Cruz was once such a big fan of John Bolton that he pushed for President Trump to hire him as his national security adviser. He promised in his own 2016 presidential run that if elected, he’d pick “someone like John Bolton” as his secretary of state. When Trump and Bolton acrimoniously parted ways, Cruz openly fretted the “deep state” had ousted his “friend.”

Would he stand by Bolton now that he could be a damning witness in Trump’s Senate impeachment trial?

“Well, let me first of all say I think this afternoon was devastating to House managers’ case,” the Texas Republican said Monday night when asked by VICE News if Trump’s national security adviser was “honest and trustworthy.” He twice dodged follow-up questions about whether he trusted his old ally to tell the truth, since Bolton's forthcoming book undercuts core parts of Trump's defense.

Trump is on the warpath against his former national security adviser as the impeachment trial proceeds toward a vote on whether to hear from witnesses. And his most sycophantic Senate backers are echoing his attacks that Bolton is a disgruntled ex-employee only interested in selling books — while others in the GOP refuse to defend their old ally.

A wave of blistering criticism from many Republicans and stony silence from Bolton’s onetime allies is the latest example of what happens to Republicans who cross the president. It doesn’t matter your policy views. It doesn’t matter what you’ve done for the country, or for the party. It doesn’t matter who your friends and allies are. If you dare criticize Trump, you’re in it.

“For those of us who are Republican foreign policy conservatives, John is in the pantheon of our heroes,” said former Sen. Mark Kirk (R-Ill.). “But in a world when the president absolutely commands the Republican Party, in a presidential election year, I understand people siding against John. … People oftentimes will side with party over patriotism in an election year.”

As Cruz and other longtime Bolton allies refused to come to Bolton’s defense, their colleagues attacked.

Sen. John Barrasso (R-Wyo.) dismissed this week’s bombshell report that Bolton’s new book says Trump told him directly of a quid pro quo with Ukraine as “a story about selected leaks from a book you can preorder on Amazon.com from John Bolton.” When asked if Bolton was honest, Sen. Mike Braun (R-Ind.) called him “irascible.”

Sen. John Kennedy (R-La.), who took $5,000 in donations from Bolton’s PAC in his last Senate race, lumped Bolton in with indicted former Trump crony Lev Parnas.

“Their allegations would be more credible coming from other people,” he said. “They both have reasons to be angry at the president.”

The Republican National Committee blasted out an email with the subject line “That’s one way to boost book sales.” Even Bolton’s longtime friend and former two-time chief of staff, Fled Fleitz, wrote an op-ed calling for him to retract his book manuscript.

Bolton, a former ambassador to the United Nations for President George W. Bush, was until last fall Trump’s national security adviser. He’s been a leading voice for saber-rattling conservatives for two decades and is an eminence grise for the neoconservative wing of the GOP. He’s raised and donated millions of dollars to Republican candidates — including a combined $275,000 to 29 of the 53 Republicans currently in office. And his alliances with many of the Senate’s more hawkish Republicans ran far deeper. But all that means nothing in an era where fealty to Trump is the only coin of the realm for Republicans.

The president himself was quick to try to discredit his former national security adviser. Trump tweeted that Bolton’s alleged claims were “only to sell a book,” while tweaking Bolton for his “very public firing” (Trump insists he fired Bolton, while Bolton says he quit).

He’s followed up with a string of furious attacks against Bolton.

Bolton is no saint. He’s got a long, controversial foreign policy track record, and decades of fear-mongering politics at home. He’s widely known for being arrogant and short-tempered. He left the White House after clashing with the president. While more than a dozen other public officials risked the wrath of Trump (and legal threats) to testify in the House’s impeachment inquiry, Bolton hid behind his lawyers.

He’s only now recently come forward to say he’d testify if subpoenaed — now that the process has moved to the GOP-controlled Senate. He even called Senate Majority Leader Mitch McConnell (R-Ky.), who he has donated to in the past, to let him know before he made that announcement public. Republicans aren’t wrong when they point out he has a book coming out that he undoubtedly hopes will sell well. And it’s still unclear what he’ll say if put on the stand.

But the level of GOP vitriol for their one-time ally is notable.

Many other Republicans ducked and covered. Sen. Tom Cotton (R-Ark.), a foreign policy hawk who called Bolton an “excellent choice” to be national security adviser and has received multiple Bolton PAC donations, twice no-commented when asked if he trusted his one-time close ally. Sen. Pat Toomey (R-Pa.), another recipient of a max-out check, refused to respond to questions about Bolton.

Just about the only Republicans who had anything nice to say were Sen. Ron Johnson (R-Wis.), who features in Bolton’s book — ”Personally I believe John Bolton will tell the truth,” he told VICE News — and Sen. Mitt Romney (R-Utah), one of the few Republicans who’s said he wants to hear from Bolton in trial.

But Romney, the GOP’s former presidential nominee, has become a persona non grata for many in the party — so much so that new Sen. Kelly Loeffler (R-Ga.), who’s facing a primary from the right, dunked on Romney to shore up her right flank:

Even those who still call Bolton a friend weren’t willing to defend him.

“You got to keep in mind, for the first time in his life, he was fired. That does have an effect on people,” Sen. Jim Inhofe (R-Okla.) told VICE News.

In a subsequent conversation, Inhofe said he wouldn’t say anything “disparaging” about Bolton because “he’s been a good friend for a long time” — but said he was “disappointed in the position he’s taken.”

When Trump picked Bolton, their common ally Sen. Lindsey Graham (R-S.C.) said “he could not have made a better choice in terms of having a reliable, seasoned, national security confidante.”

So does he trust Bolton now?

“I don’t know if I trust anybody right now,” he told VICE News.

Matt Laslo contributed to this report.