Tens of thousands of dockworkers have launched an indefinite strike at key US ports, risking major trade and economic disruption just ahead of the presidential election and the holiday shopping season. Members of the International Longshoremen's Association (ILA) walked out on Tuesday at 14 major ports along the East and Gulf Coasts, from Maine to Texas, halting container traffic. This marks the first large-scale shutdown in nearly 50 years.