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 —

With a strike deadline looming, the union for 45,000 dockworkers and the group representing East and Gulf Coast ports have exchanged wage offers, leaving a ray of hope that a deal can be reached without a major work stoppage.