By ALAN RAPPEPORT
WASHINGTON — The choice by President Trump of a pro-immigration economist to lead his Council of Economic Advisers is stirring a backlash among his most ardent supporters, who worry it is an abandonment of the tough stance he took on the issue during the campaign and the latest in a string of broken promises.
Mr. Trump had already disappointed some of his base supporters by intervening in Syria with a military strike last week and by delaying a tough stance on trade with China and Mexico. He expressed the idea via Twitter on Tuesday morning that he would be willing to offer the Chinese government a more favorable trade deal if it helped the United States with North Korea. Now there is growing unease that immigration is the next area where he will go soft.
To these supporters, the appointment of Kevin A. Hassett, announced late last Friday afternoon, as Mr. Trump’s top White House economist is another sign that the president is succumbing to the swamp he promised to drain.
Like most economists, Mr. Hassett believes that immigration spurs economic growth. At times he has pilloried Republicans for becoming the “Party of White,” arguing in 2010 that Republicans like then-Gov. Jan Brewer of Arizona “have too often appeared hostile to immigrants.” In 2013, Mr. Hassett said the United States should double its intake of immigrants.
Mr. Hassett, who currently works at the American Enterprise Institute, is a widely respected conservative economist who previously advised prominent Republicans like Senator John McCain and Mitt Romney.
But for those who backed Mr. Trump because of his promises to build a wall and deport illegal immigrants, such notions are heresy.
“It would be nice, considering how important the immigration issue has been to Trump, to have gotten an economist to this position who was at least not a booster for higher immigration,” said Mark Krikorian, executive director of the Center for Immigration Studies, an anti-immigration think tank.
Mr. Trump’s right-wing media supporters are also up in arms. Breitbart, the website that was formerly run by Stephen K. Bannon, the president’s chief political strategist, said Mr. Hassett’s appointment showed that the “corporatist, business-first” was muscling out the “populist, America-first” that got Mr. Trump elected. Commenters on the conservative website Infowars were similarly appalled, with some lamenting, “We have been sold a false bill of goods.”
Some leaders of the white nationalist “alt-right” movement also interpreted the move as a sellout. “This is yet another betrayal, just like breaking his promise to deport all illegal immigrants and to repeal President Obama’s executive amnesties,” said Jared Taylor, the editor of the online magazine American Renaissance, who spoke highly of Mr. Trump during the campaign.
Mr. Taylor said the choice of Mr. Hassett, combined with the recent airstrikes in Syria, made it “very hard to believe anything he says.”
The controversy follows decades of grappling within the Republican Party over how to address immigration. After some party leaders considered a more inclusive approach, Mr. Trump swung the party to the right as a candidate when he painted immigrants as criminals who were stealing American jobs and depressing wages.
Such pronouncements amplified voices within the Republican Party that have been fearful about both illegal and legal immigration. Last month, Representative Steve King, an Iowa Republican who is a strong supporter of Mr. Trump, caused an uproar when he said, “You cannot rebuild your civilization with somebody else’s babies.”
Some Republicans in the Senate, including Senator Tom Cotton of Arkansas, have also been focusing on limiting legal immigration. Mr. Cotton has proposed legislation that would narrow the scope of the permanent resident green card system and reduce access to visas.
On Tuesday, Attorney General Jeff Sessions traveled to the border with Mexico and laid out a tougher approach the administration will be taking with people who sneak into the country. Those measures include federal prosecutions.
But despite his tough tone as a candidate, Mr. Trump has shown some signs of moderation as president. He said he welcomed immigrants who love the country and bring valuable skills and strong work ethics. And he has yet to unravel President Barack Obama’s Deferred Action for Childhood Arrivals program for the so-called Dreamers, as Mr. Krikorian ruefully noted.
Economists who have been wary of the recent wave of anti-immigrant sentiment are hopeful that Mr. Hassett will be an influential voice in the administration to encourage a more welcoming approach.
On Wednesday, a group of 1,470 economists, both conservative and liberal, are sending a letter to Mr. Trump and congressional leaders urging them to consider policies that allow more immigrants into the country legally. They contend that the economic benefits outweigh the costs. (Mr. Hassett did not sign the letter, which was organized by New American Economy, a coalition of mayors and business leaders.)
“Immigration is really not a debatable issue,” said James Miller, who led President Ronald Reagan’s Office of Management and Budget and signed the letter. “Immigration is a good idea if you control it the right way.”
Mr. Hassett declined an interview request after his appointment was announced. A White House spokeswoman, Lindsay Walters, dismissed the negative reaction, pointing to his decades of experience in economics, and said, “The president is confident he will work tirelessly to improve the economy for all Americans and looks forward to welcoming him onboard following his confirmation.”
It remains unclear, however, how much influence Mr. Hassett will actually have. Mr. Trump broke with recent tradition and removed the council’s chairman from a cabinet-level position. He has also expressed skepticism about economics in the past by casting doubt on official government employment statistics and expert opinions about the health of the economy.
For those reasons, some who have been critical of Mr. Trump are tempering their optimism about Mr. Hassett.
“He might be a sign of some stability, but no one knows if the president is going to listen to him, so it’s premature to say it is encouraging,” said Austan Goolsbee, who was chairman of Mr. Obama’s Council of Economic Advisers. “Regarding his critics, there is not a single reputable economist they could find in either party that would support their worldview.”