But many existing American manufacturing jobs depend heavily on access to a broad array of goods drawn from a global supply chain — fabrics, chemicals, electronics and other parts. Many of them come from China. At Mr. Reid’s factory, imports account for roughly two-thirds of the cost of making a recliner chair.

In short, Mr. Trump’s signature trade promise, one ostensibly aimed at protecting American jobs, may well deliver the reverse: It risks making successful American manufacturers more vulnerable by raising their costs. It would unleash havoc on the global supply chain, prompting some multinationals to leave the United States and shift manufacturing to countries where they can be assured of buying components at the lowest prices.

“If you do this tomorrow, you would have a lot of disruption,” said Susan Helper, an economist at the Weatherhead School of Management at Case Western Reserve University in Cleveland. “The stuff that China now makes and the way they make it, it’s not trivial to replicate that.”