Members of the International Longshoremen’s Association walked out for the first time since 1977 in a standoff over wages, benefits and job security.

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 seaports on the East and Gulf Coasts went on strike Tuesday after negotiations with port employers over a new contract remained at an impasse.