WASHINGTON — The White House indicated on Sunday that President Trump would accept new legislation curtailing his authority to lift sanctions on Russia on his own, a striking turnaround after a broad revolt by lawmakers of both parties who distrusted his friendly approach to Moscow and sought to tie his hands.
If it passes, as now seems likely, the measure will represent the first time that Congress, with both houses controlled by fellow Republicans, has forced its will on Mr. Trump on a major policy matter. That it comes on an issue as fraught as Russia illustrates how investigations into possible collusion between Moscow and Mr. Trump’s team during last year’s election have cost him politically.
The legislation may also have long-term consequences for the American relationship with Russia and for the power of the presidency. Once sanctions are written into law, they are much harder to lift, even long after the circumstances prompting them have changed, which is one reason European allies opposed the bill. And presidents from both parties have long resisted Congress’s inserting itself into the process of determining foreign policy through mandatory sanctions.
But Mr. Trump found himself in a no-win position, as lawmakers eager to punish Russia for its interference in the election and its aggression toward its neighbors dispensed with the usual partisan divide. Mr. Trump, who has made it a priority to establish warm relations with President Vladimir V. Putin of Russia, lashed out in anger at both parties on Sunday.
“As the phony Russian Witch Hunt continues, two groups are laughing at this excuse for a lost election taking hold, Democrats and Russians!” Mr. Trump wrote on Twitter. He then added, “It’s very sad that Republicans, even some that were carried over the line on my back, do very little to protect their President.”
The outburst contrasted with the efforts of his staff to argue that the sanctions measure had been improved. With little chance of blocking it, the White House was left to declare that changes to the original legislation made in an agreement announced over the weekend were enough to satisfy the president’s concerns.
“The administration is supportive of being tough on Russia, particularly in putting these sanctions in place,” Sarah Huckabee Sanders, the new White House press secretary, said on “This Week” on ABC. “The original piece of legislation was poorly written, but we were able to work with the House and Senate, and the administration is happy with the ability to do that and make those changes that were necessary, and we support where the legislation is now.”
Still, there seemed to be confusion among the president’s advisers. Anthony Scaramucci, the new White House communications director, said on another show that the president had not decided whether to sign the measure. “You’ve got to ask President Trump that,” he said on “State of the Union” on CNN. “It’s my second or third day on the job. My guess is he’s going to make that decision shortly.” He added, “He hasn’t made the decision yet to sign that bill one way or the other.”
That seemed mainly to reflect the fact that Mr. Scaramucci was still getting up to speed in his new role. “My bad,” Mr. Scaramucci said by text when asked about the different comments. “Go with what Sarah is saying as I am new to the information.”
Privately, other White House officials said that although the president would not publicly commit to signing the bill until seeing the final version, they saw no politically viable alternative if it arrived at his desk as currently written. So Ms. Sanders seized on the changes made to lay the predicate for his expected signature.
In reality, while the changes made the measure somewhat more palatable to the White House and to energy companies that objected, they mainly provided a way for the president to back down from a confrontation he was sure to lose if the sanctions bill reached the floor of the House. The Senate passed the original version of the bill, 97 to 2, and the new version, which also includes sanctions on Iran and North Korea, may come to a vote in the House as early as Tuesday.
“In the end, the administration will come to the conclusion that an overwhelming majority of Congress has, and that is that we need to sanction Russia for their meddling in the U.S. election,” Senator John Thune, Republican of South Dakota, said on “Fox News Sunday.” “That, I think, will pass probably overwhelmingly again in the Senate and with a veto-proof majority.”
Senator Benjamin L. Cardin, Democrat of Maryland and a longtime leader in pressing for more sanctions on Russia, particularly for human rights abuses, put it bluntly on the same program. “If he vetoes the bill,” Mr. Cardin said, “we will override his veto.”
Russia has bristled at American sanctions for years, particularly since the United States began imposing them under President Barack Obama in 2014 after Moscow’s annexation of Crimea and intervention in eastern Ukraine. Donald Trump Jr., the president’s eldest son, said Russian visitors with Kremlin ties raised separate human rights sanctions at a meeting during last year’s campaign, and his father said Mr. Putin raised them with him this month during a summit meeting in Germany.
The Kremlin said over the weekend that it took an “extremely negative” view of the new congressional measure but sought to dismiss the impact of its provisions. Russian news outlets noted on Sunday that the bill appeared less severe than feared.
“Vesti Nedeli,” the flagship news program of Rossiya 1, a state-owned television channel, gave only a brief summary of the new legislation, focusing instead on the Obama administration’s seizure in December of two Russian diplomatic compounds in Maryland and New York.
Although many sanctions laws passed by Congress give the president the authority to waive their provisions if he deems it in the national interest, lawmakers this time tried to limit Mr. Trump’s latitude. To lift sanctions related to Ukraine, Mr. Trump would have to certify that conditions prompting them had been reversed. To lift sanctions over Russian cyberattacks, he would have to provide evidence that Russia had tried to reduce such intrusions. And Congress would have at least 30 days to vote on any changes he sought.
Mr. Trump came to office seemingly determined to lift at least some sanctions on Russia. In the early days of his administration, a plan was drafted to reverse measures taken by Mr. Obama in his final weeks in office in retaliation for Russia’s meddling in the election. The plan discussed by Mr. Trump’s aides was throttled after Republican congressional leaders warned against it.
Administration officials now say that Mr. Trump supports the array of sanctions on Russia, particularly stemming from Ukraine, and will not cancel them until Moscow reverses course there. Still, Russia has demanded the return of the two diplomatic properties, and the Trump administration has not ruled that out.
The stand-down on the sanctions fight came at the start of a week in which Donald Trump Jr.; the president’s son-in-law and senior adviser, Jared Kushner; and his former campaign chairman, Paul J. Manafort, are all set to talk with congressional investigators. White House aides on Sunday sought to explain the president’s assertion on Twitter on Saturday that he has the “complete power to pardon” his relatives and advisers — and possibly himself.
Jay Sekulow, a private lawyer representing Mr. Trump, said the president was simply asserting his authority after The Washington Post reported that he was discussing it. But Mr. Sekulow denied that pardons were being considered. “We’re not researching the issue, because the issue of pardons is not on the table. There’s nothing to pardon from,” he said on ABC.
Yet Mr. Scaramucci acknowledged that the president had raised the matter. “I’m in the Oval Office with the president last week; we’re talking about that,” Mr. Scaramucci said on Fox. “He brought that up. He said, but he doesn’t have to be pardoned. There’s nobody around him that has to be pardoned. He was just making the statement about the power of pardons.”