Whenever and however the dispute is resolved, it's likely to affect how freight moves in and out of the United States for years to come. If a strike were resolved within a few weeks, consumers probably wouldn't notice any major shortages of retail goods.

About 45,000 dockworkers along the U.S. East and Gulf Coasts are threatening to strike on Oct. 1, a move that would shut down ports that handle about half the nation's cargo from ships.