U.S. President Donald Trump has vowed that his historic tariff blitz would revive domestic manufacturing, but industry worries about his approach are raising fresh doubts about whether he can deliver on his promise of an economic boom.

In the Rose Garden on Wednesday, Trump declared "jobs and factories will come roaring back into our country” and predicted new "golden age” in America. Since then, he has stood by his decision to hike U.S. tariffs to their highest levels in more than a century, even as the move sparked a global market meltdown.

Some manufacturing advocates and economists questioned Trump’s underlying logic, saying supply chain issues, high costs, workforce needs and the laborious process of moving production to the U.S. stand in the way. Continued uncertainty about Trump’s long-term policy could also have a chilling effect, they said.