U.S. ports from Maine to Texas could shut down Tuesday if a union representing about 45,000 dockworkers carries through with a threatened strike. A lengthy shutdown could raise prices on goods around the country and potentially cause shortages and price increases at big and small retailers alike as the holiday shopping season — along with a tight presidential election —

The Taft-Hartley Act authorizes the president to temporarily prevent strikes so bargaining parties can try to settle. Biden has said he won’t intervene.