Republicans are privately grumbling about President Trump’s economy as fears of a recession and turmoil on Wall Street overshadow manufacturing job gains and cooling inflation.

Republican lawmakers in Washington publicly support the president and his aggressive use of tariffs, but behind the scenes, some worry about budding economic uncertainty and possible backlash at the ballot box.

The economic angst is palpable across the U.S., where Mr. Trump won the presidential election in a landslide last year.

Ashli Watts, president and CEO of the nonpartisan Kentucky Chamber of Commerce, said business owners are worried.

“We are starting to get concerned, especially with the tariffs. We make cars and bourbon in Kentucky,” Ms. Watts said. “We have been a business community that was cautiously optimistic about the new administration and removing some of the regulations of the last four years, but the tariffs could hit just as hard as the regulations.”

The European Union has threatened to retaliate against new U.S. tariffs with a 50% duty on American whiskey, which supports more than 23,000 jobs in Kentucky.

Automakers are bracing for high costs from 25% tariffs on steel and aluminum that went into effect Wednesday.

Republicans on Capitol Hill are grousing among themselves about the uptick in complaints from business owners and other constituents who fear economic pain from trade wars. Publicly, however, few will challenge Mr. Trump on the economy.

Sen. John Kennedy of Louisiana said answering reporters’ questions about economic fears is a no-win proposition for him and other Republicans.

“If I say no, I’m a bad senator. If I say yes, you’re going to print that I have concerns, and neither of those are accurate. I worry about social and economic issues every day,” he said.

Others characterize doubts about Mr. Trump’s economy in strictly political terms.

“Those who don’t like President Trump don’t like it, and those who supported President Trump — Montana voted by 20 points for Trump — are pleased to see him taking action,” said Sen. Steve Daines, Montana Republican.

Still, the headlines have given Americans plenty of reasons to fret.

Mr. Trump recently refused to rule out a recession caused by his tariffs, triggering a massive stock market sell-off. On Thursday, Mr. Trump threatened 200% tariffs on wine and other alcoholic beverages from the European Union. The president has also engaged in tariff fights with America’s biggest trading partners: Canada, Mexico and China.

Consumer sentiment fell 10% last month, according to a University of Michigan survey.

White House senior trade adviser Peter Navarro blamed the media for some of the economic anxiety. He said the market reacts to news coverage, which he characterized as negative about the president and his policies.

“The media, the legacy media in particular, has published far more negative stories than positive. But when you write or broadcast that there’s going to be wild inflation and recession and set people’s hair on fire, that does possibly have impacts on consumer confidence,” he told reporters at the White House.

“When you do that without justifiable data to back it up, as some of you have been doing, it doesn’t serve the purpose of the country. You actually do harm when you do that,” he said.

The White House is trying to play the long game and urging patience. Mr. Trump has characterized the stock market losses as temporary disruptions that will smooth out once his tariff policies are firmly in place.

That approach carries the risk of voters souring on Mr. Trump’s economic agenda before it can produce benefits. It also puts the administration in a difficult position to explain why a president elected mainly on his pledge to boost the economy is surrounded by economic uncertainty.

Some economic news is positive.

Inflation cooled last month, with consumer prices up 2.8% from February 2024. It was below the 3.2% increase predicted by Wall Street economists.

The inflation numbers released Wednesday predate Mr. Trump’s recent tariff actions, and the full effect of the tariffs will be revealed in future reports.

A key bright spot in the report was the cooling of housing and rent prices, significant sources of inflationary pressure. They were up 4.2% from a year ago, the smallest gain since December 2021.

A Labor Department report revealed that 151,000 jobs were created during Mr. Trump’s first month in office, 93% in the private sector. Among them were 10,000 manufacturing jobs, including 9,000 in the automobile sector. In 2024, 111,000 manufacturing jobs were lost.

White House spokesman Kush Desai said the president’s economic policies are taking root. He noted the hundreds of billions of dollars in investments from companies such as Taiwan Semiconductor Manufacturing Co. and drugmaker Eli Lilly.

“Since President Trump was elected, industry leaders have responded to President Trump’s ‘America First’ economic agenda of tariffs, deregulation and the unleashing of American energy with trillions in investment commitments that will create thousands of new jobs,” he said. “President Trump delivered historic job, wage and investment growth in his first term and is set to do it again in his second term.”

• Kerry Picket contributed to this report.