The north benefited from the global search for alternatives to Chinese manufacturing. No one knows whether a second Trump term will impede or accelerate that growth.

The move escalates supply chain warfare and comes a day after the Biden administration expanded curbs on the sale of advanced American technology to China.

A series of swipes at American companies show how China could take the initiative in a new trade war, using its economic dominance to exact pain.

The president-elect’s threat to hit Canada, Mexico and China with new tariffs is already rocking business and diplomatic relationships and could topple the trade pacts he signed in his first term.

Companies are filling their warehouses or looking into moving factories as they weigh President-elect Donald J. Trump’s threats to impose tariffs on foreign goods.

Already the dominant producer of rare minerals, Beijing is using export restrictions and its power over state-owned companies to further control access.