Nearly 50,000 members of the International Longshoremen’s Association (ILA) are on strike Tuesday against the nation’s East and Gulf Coast ports, choking off the flow of many of America’s imports and exports in what could become the country’s most disruptive work stoppage in decades.

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 —