Kia opened a factory in Georgia in 2009. Part of the draw was the port, which was already knee deep in its infrastructure overhaul. The company was impressed, said Corinne Hodges, a spokeswoman for Kia, with “how quickly can a truck get in and out and how fast can freight get off the boat and get its way into the plant.”

Savannah has also benefited from some unanticipated assistance. Labor troubles caused a monthslong slowdown at the nation’s largest port complex in Los Angeles, stranding cargo on ships and frustrating retailers with tight deadlines. The episode pushed importers and shipping lines to diversify their points of entry and better acquainted them with the efficiencies of Savannah’s port.

That may be why union leaders here emphasize that no matter what happens, they intend to keep the cargo moving.

“We don’t think the administration is out to hurt anybody” with its trade policy, said Timothy S. Mackey, president of the 1,500-member Local 1414 of the International Longshoremen’s Association. “Trump is a competitive guy, a businessman. He wants the best deal.”

“But we’ll do what we need to do,” he said. “The world keeps moving.”