History suggests that a cycle of tariffs and retaliations can eventually choke economic growth. But for now, employers, investors and U.S. consumers are weighing the perils of a prolonged rift between the world's two largest economies against a far more positive backdrop: America's healthiest job market in years.

Evidently confident despite the risks ahead, U.S. employers have added jobs this year at a robust monthly average of 214,500. Many businesses say they've reached the point where they can't even find enough people to fill jobs. Unemployment is at a low 4 percent.