By JENNIFER STEINHAUER – THE NEW YORK TIMES
WASHINGTON — Senate Republicans, increasingly unnerved by President Trump’s volatility and unpopularity, are starting to show signs of breaking away from him as they try to forge a more traditional Republican agenda and protect their political fortunes.
Several Republicans have openly questioned Mr. Trump’s decision to fire the F.B.I. director, James B. Comey, and even lawmakers who supported the move have complained privately that it was poorly timed and disruptive to their work. Many were dismayed when Mr. Trump seemed to then threaten Mr. Comey not to leak negative information about him.
As they pursue their own agenda, Republican senators are drafting a health care bill with little White House input, seeking to avoid the public relations pitfalls that befell the House as it passed its own deeply unpopular version. Republicans are also pushing back on the president’s impending budget request — including, notably, a provision that would nearly eliminate funding for the national drug control office amid an opioid epidemic. And many high-ranking Republicans have said they will not support any move by Mr. Trump to withdraw from the North American Free Trade Agreement.
So far, Republicans have refrained from bucking the president en masse, in part to avoid undermining their intense push to put health care and tax bills on his desk this year. And the Republican leadership, including Senator Mitch McConnell of Kentucky, the majority leader, and the House speaker, Paul D. Ryan of Wisconsin, remains behind Mr. Trump.
But with the White House lurching from crisis to crisis, the president is hampering Republicans’ efforts to fulfill his promises.
“All the work that goes into getting big things done is hard enough even in the most tranquil of environments in Washington,” said Kevin Madden, a Republican operative who worked for John A. Boehner when he was the House speaker. “But distractions like these can become a serious obstacle to aligning the interests of Congress.”
When Congress and the White House are controlled by the same party, lawmakers usually try to use the full weight of the presidency to achieve legislative priorities, through a clear and coordinated vision, patience with intransigent lawmakers and message repetition. Mr. Trump’s transient use of his bully pulpit for policy messaging has upended that playbook.
“It does seem like we have an upheaval, a crisis almost every day in Washington that changes the subject,” Senator Susan Collins, Republican of Maine, who has been trying to advance health care legislation, said in a television interview on Thursday night.
The latest subject-changing crisis has been the fallout from Mr. Trump’s sudden dismissal of Mr. Comey, who was leading the F.B.I.’s investigation into contacts between the Trump campaign and Russia. Mr. Trump suggested last week that he might have surreptitiously taped his conversations with Mr. Comey, and on Sunday two Republican senators, Mike Lee of Utah and Lindsey Graham of South Carolina, said the president should turn over any such tapes, if they exist.
In the days after Mr. Trump’s election victory, the mood was different, as Republicans expressed high hopes that they could move quickly on a conservative agenda that merged with Mr. Trump’s. “We’re going to be an enthusiastic supporter almost all the time,” Mr. McConnell said of Mr. Trump in November.
But Republicans have so far achieved few of their legislative priorities, like repealing the Affordable Care Act or cutting taxes. When Mr. Trump suggested this month that the Senate should change its rules to make it easier for Republicans to push bills through, Mr. McConnell firmly rejected the idea.
Lawmakers are also bucking the president by pushing ahead with bipartisan measures on sanctions against Russia. And this month, Republicans rejected many of the administration’s priorities in a short-term spending measure, including money for a wall along the border with Mexico.
Two Republican senators who face potentially tough re-election fights next year — Dean Heller of Nevada and Jeff Flake of Arizona — have been unabashed in their criticism of Mr. Trump and his administration, which they have clearly begun to view as a drag on their political prospects.
“In Arizona, we grow them independent,” Mr. Flake said, noting the unpopularity in his state of Mr. Trump’s views on the border wall and Nafta. “I expect people want someone who will say, ‘I’m voting with Trump on the good stuff and standing up to him on the not good stuff.’”
Some Republicans, like Mr. Ryan, have preferred to keep the focus firmly on the good stuff. Mr. Ryan has remained in harmony with the president, last month calling him “a driven, hands-on leader, with the potential to become a truly transformational American figure.”
Mr. Trump retains the support of about 80 percent of Republican voters, and although his overall popularity is at historic lows at this point in a presidency, it remains well above the depths eventually reached by presidents like George W. Bush and Jimmy Carter. At those levels, larger numbers of lawmakers might start to turn away from Mr. Trump — though even if they wanted to do so, Republicans would not be able to completely separate themselves from him on issues like a tax overhaul, where his blessing would be needed to move forward in any major way.
But while Mr. Trump’s approval rating has been sufficient to prevent mass defections — a Wall Street Journal/NBC News poll released on Sunday showed it at 39 percent — it is too low to pressure Democrats to support him in any significant way.
Any bills that require 60 votes to pass — almost everything aside from Republicans’ health care and tax measures — will be impossible to advance without the help of Democrats.
Republicans had been counting on Senate Democrats who are up for re-election next year in states won by Mr. Trump to bend to their will. But so far those Democrats, like Senators Claire McCaskill of Missouri and Joe Manchin III of West Virginia, have been largely comfortable standing against Mr. Trump, especially when their Republican colleagues tell them that they, too, have had about enough.
“I’m hearing more and more of them say privately that they are more and more concerned,” said Senator Sherrod Brown, Democrat of Ohio. “More importantly, there is a lot less fear of him than there was just a month ago.”
Already, Republicans are talking openly about rejecting components of the budget request that Mr. Trump is expected to release in two weeks. Any new request for money for a border wall would almost certainly be rejected, as would large cuts to drug control programs.
Senator Rob Portman, Republican of Ohio, has spoken in support of the programs on the Senate floor, and Senator Shelley Moore Capito, Republican of West Virginia, which has had large numbers of opioid deaths, issued a news release calling on the administration to “propose a realistic budget that demonstrates the administration’s commitment to combating drug addiction.”
If it does not, she warned in a letter to Mick Mulvaney, the White House budget director, “I will lead a bipartisan group of my colleagues on the Appropriations Committee and in the Senate to reject those proposed cuts.”
During his campaign, Mr. Trump found a winning message in criticizing trade agreements. But traditionally pro-trade Republicans — after yielding for a while to his rejection of such deals, including when he abandoned the Trans-Pacific Partnership on his first full weekday in office — have begun to push back. The president has vacillated on whether to also abandon Nafta.
“If you cancel Nafta, you harm the economy of my state,” said Senator John McCain, Republican of Arizona. Mr. Flake concurred: “Our trade relationship with Mexico is a positive, and not just in an economic sense, but in terms of security as well,” he said, citing cooperation between Mexican and American authorities on combating drug trafficking.
Mr. Trump should also not expect Congress to give Russia a pass over its actions in Ukraine, Syria and the 2016 American election.
“My sense is that Congress is going to act on sanctions against Russia,” said Senator Bob Corker, Republican of Tennessee and the chairman of the Senate Foreign Relations Committee, which is working on bills now. “We plan to be very much in the middle of that.”
Even some of Mr. Trump’s most fervent backers see tensions in the future.
“There will be times when we disagree with the president,” said Senator Jim Inhofe, Republican of Oklahoma, who has criticized the administration for what he perceives as the possibility that it will keep the country in the Paris climate accord. “And we when do, we’ll be outspoken about it.”
A version of this article appears in print on May 15, 2017, on Page A1 of the New York edition with the headline: Senate G.O.P. Is Edging Back From President.