WASHINGTON — President Trump made dozens of promises when he campaigned to retake the White House last year, from boosting economic growth to banning transgender athletes from girls’ sports.

But one pledge stood out as the most important in many voters’ eyes: Trump said he would not only bring inflation under control, but push grocery and energy prices back down.

“Starting the day I take the oath of office, I will rapidly drive prices down, and we will make America affordable again,” he said in 2024. “Your prices are going to come tumbling down, your gasoline is going to come tumbling down, and your heating bills and cooling bills are going to be coming down.”

He hasn’t delivered. Gasoline and eggs are cheaper than they were a year ago, but most other prices are still rising, including groceries and electricity. The Labor Department estimated Thursday that inflation is running at 2.7%, only a little better than the 3% Trump inherited from Joe Biden; electricity was up 6.9%.

And that has given the president a major political problem: Many of the voters who backed him last year are losing faith.

“I voted for Trump in 2024 because he was promising America first … and he was promising a better economy,” Ebyad, a nurse in Texas, said on a Focus Group podcast hosted by Bulwark publisher Sarah Longwell. “It feels like all those promises have been broken.”

Since Inauguration Day, the president’s job approval has declined from 52% to 43% in the polling average calculated by statistician Nate Silver. Approval for Trump’s performance on the economy, once one of his strongest points, has sunk even lower to 39%.

That’s dangerous territory for a president who hopes to help his party keep its narrow majority in elections for the House of Representatives next year.

To Republican pollsters and strategists, the reasons for Trump’s slump are clear: He overpromised last year and he’s under-performing now.

“The most important reasons he won in 2024 were his promises to bring inflation down and juice the economy,” Republican pollster Whit Ayres said. “That’s the reason he won so many voters who traditionally had supported Democrats, including Hispanics. … But he hasn’t been able to deliver. Inflation has moderated, but it hasn’t gone backward.”

Last week, after deriding complaints about affordability as “a Democrat hoax,” Trump belatedly launched a campaign to convince voters that he’s at work fixing the problem.

But at his first stop, a rally in Pennsylvania, he continued arguing that the economy is already in great shape.

“Our prices are coming down tremendously,” he insisted.

“You’re doing better than you’ve ever done,” he said, implicitly dismissing voters’ concerns.

He urged families to cope with high tariffs by cutting back: “You know, you can give up certain products,” he said. “You don’t need 37 dolls for your daughter. Two or three is nice, but you don’t need 37 dolls.”

Earlier, in an interview with Politico, Trump was asked what grade he would give the economy. “A-plus-plus-plus-plus-plus,” he said.

On Wednesday, the president took another swing at the issue in a nationally televised speech, but his message was basically the same.

“One year ago, our country was dead. We were absolutely dead,” he said. “Now we’re the hottest country anywhere in the world. … Inflation is stopped, wages are up, prices are down.”

Republican pollster David Winston, who has advised GOP members of Congress, said the president has more work to do to win back voters who supported him in 2024 but are now disenchanted.

“When families are paying the price for hamburger that they used to pay for steak, there’s a problem, and there’s no sugarcoating it,” he said. “The president’s statements that ‘we have no inflation’ and ‘our groceries are down’ have flown in the face of voters’ reality.”

Another problem for Trump, pollsters said, is that many voters believe his tariffs are pushing prices higher — making the president part of the problem, not part of the solution. A YouGov poll in November found that 77% of voters believe tariffs contribute to inflationary pressures.

Trump’s popularity hasn’t dropped through the floor; he still has the allegiance of his fiercely loyal base. “He is at his lowest point of his second term so far, but he is well within the range of his job approval in the first term,” Ayres noted.

Still, he has lost significant chunks of his support among independent voters, young people and Latinos, three of the “swing voter” groups who put him over the top in 2024.

Inflation isn’t the only issue that has dented his standing.

He promised to lead the economy into “a golden age,” but growth has been uneven. Unemployment rose in November to 4.6%, the highest level in more than four years.

He promised massive tax cuts for the middle class, but most voters say they don’t believe his tax cut bill brought them any benefit. “It’s hard to convince people that they got a tax break when nobody’s tax rates were actually cut,” Ayres noted.

He kept his promise to launch the largest deportation campaign in U.S. history — but many voters complain that he has broken his promise to focus on violent criminals. In Silver’s average, approval of his immigration policies dropped from 52% in January to 45% now.

A Pew Research Center survey in October found that 53% of adults, including 71% of Latinos, think the administration has ordered too many deportations. However, most voters approve of Trump’s measures on border security.

Republican pollsters and strategists say they believe Trump can reverse his downward momentum before November’s congressional election, but it may not be easy.

“You look at what voters care about most, and you offer policies to address those issues,” GOP strategist Alex Conant suggested. “That starts with prices. So you talk about permitting reform, energy prices, AI [artificial intelligence] … and legislation to address healthcare, housing and tax cuts. You could call it the Affordability Act.”

“A laser focus on the economy and the cost of living is job one,” GOP pollster Winston said. “His policies on regulation, energy and taxes should have a positive impact, but the White House needs to emphasize them on a more consistent basis.”

“People voted for change in 2024,” he warned. “If they don’t get it — if inflation doesn’t begin to recede — they may vote for change again in 2026.”