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 —

Dockworkers at East and Gulf Coast ports are on the verge of a strike that could begin Tuesday, raising questions about whether West Coast ports can absorb stalled shipments.

Thousands of dockworkers at more than a dozen ports along the East Coast and Gulf Coasts are poised to walk off the job on Tuesday.