President Barack Obama is giving up on some of the American manufacturing jobs that went to Mexico, telling an Indiana resident that many of those jobs are not coming back.

During a town hall in Elkhart, Indiana, Obama was asked a question about manufacturing by a man who was once employed by Carrier Corporation in Indiana before the plant announced plans to move to Mexico.

“What we have to do is to make sure that folks are trained for the jobs that are coming in now because some of those jobs of the past are just not going to come back,” Obama said bluntly during the event broadcast on PBS.

Carrier announced in February that it would move 1,400 jobs to Mexico — even after receiving $5.1 million from the Obama administration in clean energy tax credits. Carrier later clarified in a statement that it will not claim the federal tax credit.

Republican presidential candidate Donald Trump has cited Carrier specifically on the campaign trail, saying it’s one more sign of American decline.

“I wanna do the number on Carrier, folks. I don’t like what they did,” Trump said in April, vowing to bring the jobs back.

But Obama was skeptical that Trump could fulfill his promise.

“There’s no answer to it. He just says, ‘Well, I’m going to negotiate a better deal.’ Well, how exactly are you going to negotiate that? What magic wand do you have?” Obama asked. “And usually, the answer is he doesn’t have an answer.”

Obama insisted that the “good old days” of manufacturing were over, thanks to technology.

“The days when you just being willing to work hard and you can now walk into a plant and suddenly there’s going to be a job for you for 30 years or 40 years, that’s just not going to be there for our kids,” Obama said.

He blamed technology and automation for the decreasing level of manufacturing jobs, suggesting that free community college would help students learn the skills necessary to compete for high tech jobs.

“[Y]ou cannot look backwards, and that doesn’t make folks feel good sometimes, especially if it’s a town that was reliant on a couple of big manufacturers,” he said. “But they’re going to have to retrain for the jobs of the future, not the jobs of the past.”