Not the tweets, the Russian issue or Comey’s firing: So what will it take for Republicans to break with Trump?

They fume privately at President Trump’s coziness with the Russians. They wince almost every time he tweets. They talk among themselves about what might have been with a different Republican in the White House.

Yet even as each new crisis seems like it might be the event that moves GOP lawmakers away from Trump, key Republican leaders and rank-and-file members circle the White House, protecting the president from attack and shifting the blame to Democrats and the media.

Tuesday brought the sternest test yet of Republican willingness to stand with the president, as multiple news organizations reported that Trump had personally asked then-FBI Director James B. Comey to drop the bureau’s investigation of former national security adviser Michael Flynn.

The news — denied by the White House — hit a Congress that already was stunned by Trump’s firing of Comey last week and his sharing of intelligence with Russian diplomats.

Whether the latest allegations will prove to be the tipping point for more GOP lawmakers remains to be seen, but initial reactions suggested many were standing behind the president.

Senate Intelligence Committee Chairman Richard M. Burr (R-N.C.), who had voiced frustration over Trump’s information-sharing with the Russians, cast doubt Tuesday evening on news reports that Trump had tried to stop the Flynn probe.

“I actually believe the director might have told us that there’d been a request like that, and it was never mentioned by him,” Burr said. “So somebody’s going to have to do more than have anonymous sources on this one for me to believe that there’s something there.”

Rep. Louie Gohmert (R-Texas) said it “almost sounds like fake news.”

But centrist Republican Rep. Carlos Curbelo of Florida said that if the Comey allegations were true, “it would be deeply, deeply troubling, disconcerting and it would open a new chapter of scandal.”‬

In some ways, it’s little surprise that Republicans in Congress are supporting Trump. Lawmakers are largely reflecting their constituents, and polling shows Republican voters, and those who cast ballots for Trump, still overwhelmingly back the president.

But more to the point, if Republicans were to break ranks with the White House and begin to question Trump’s ability to govern, what would happen next?

Any acknowledgement by Republicans that Trump’s actions are unacceptable would lead to inevitable questions about what exactly Congress planned to do about it. And Republicans don’t appear ready to answer that.

Very few Republicans have joined Democrats in seeking a special prosecutor or independent panel to investigate the Trump campaign’s possible ties to Russian meddling in the election — much less in the calls for impeachment.

On Tuesday, however, Rep. Steve Knight of Palmdale became the third House Republican from California to back a special prosecutor. “There is so much conflicting information from many sources; Americans deserve the opportunity to learn the truth,” he said in a statement.

The dilemma for Republicans was on full display Tuesday in conversations and statements on Capitol Hill. While a handful of GOP lawmakers voiced rising concern over Trump’s behavior, many stood by the president.

“This man is subject to more criticism than anybody, any predecessor that I know of,” said Sen. Orrin G. Hatch (R-Utah). “It was a remarkable election and they can’t stand it, so they’re going to do everything they can to destroy him. It’s just that simple.”

Sen. Richard C. Shelby (R-Ala.), former chairman of the Intelligence Committee, said most new administrations have a rough start.

“Look at President Clinton: When he started off, he had a real bumpy road for about a year and a half,” Shelby said. “Let’s see what happens the next six, seven months. Everything’s another day.”

Republicans are loathe to derail their opportunity to make good on promises to cut taxes, repeal Obamacare and undo federal regulations as they control the White House and Congress. They know a Trump White House embroiled in scandal and investigations would be effectively crippled, and already the GOP legislative agenda has been overshadowed.

Trump is “trying to accomplish a number of things we ran on, so he’s got quite a bit of support,” said Sen. Roger Wicker (R-Miss.). “It doesn’t help to have a controversy swirling, but I can’t say that’s it’s distracting us from getting things done.”

Democrats, appalled by Trump’s behavior, are pushing Republicans to move beyond partisanship.

“The country is being tested in unprecedented ways,” said Senate Minority Leader Charles E. Schumer. “I say to all of my colleagues in the Senate: History is watching.”

Democrats are demanding transcripts of Trump’s conversation with the Russian ambassador and foreign minister as well as any tape recordings Trump may have made in relation to his contact with Comey.

After the New York Times reported that Comey had kept private memos of his conversations with Trump, including the one in which he claimed Trump asked him to drop the Flynn probe, Democrats are pushing to see those records as well.

A few Republicans are ready to join that effort. “I have my subpoena pen ready,” said Jason Chaffetz (R-Utah), chair of the House oversight committee.

But Democrats’ plea to Republicans so far has proved little match for Trump’s staying power and ability to survive political missteps that would fell other politicians.

During the presidential campaign, when a recording emerged of Trump boasting about sexually groping women with impunity because of his celebrity status, many Republicans, including House Speaker Paul D. Ryan, distanced themselves from his campaign.

But then Republican voters by and large gave their candidate a pass, and Ryan and others had to scramble to mend their relationship with him.

Many GOP lawmakers continue to say the media is treating Trump unfairly.

“He is, I think, having a volatile ride from a media perspective, but the underlying policies that I think are good for the country — tax reform, healthcare reform, rolling back the regulatory agenda of the past administration — all of these have a very consistently positive impact,” said Sen. Tim Scott (R-S.C.).

Others could not easily put an optimistic spin on the concerns churning from the White House.

“These are daily — well, not daily, hopefully, but seems like lately daily — distractions, and you just have to manage around it,” said the Senate’s slightly exasperated No. 3 Republican, John Thune of South Dakota. “We’re proceeding according to plan, but less drama on the other end of Pennsylvania Avenue would be a good thing.”

Centrist Republicans were those most eager to distance themselves from Trump.

Rep. Adam Kinzinger (R-Ill.) tweeted Tuesday: “Sharing classified info to one of our enemies is a threat to our national security, troops on the ground & relationships w/ trusted allies.”

Said Rep. Barbara Comstock, who is in a highly competitive swing district in the affluent North Virginia suburbs: “Once again we are faced with inexplicable stories coming from the White House that are highly troubling.”

Asked whether he trusted Trump to handle classified information, Sen. Bob Corker (R-Tenn.) — who Monday warned of the White House’s “downward spiral” — turned and shrugged: “Sure.”

lisa.mascaro@latimes.com

@LisaMascaro