Summary: Next week, the contract between 340,000 unionized workers and UPS expires. Workers authorized a strike and say they are ready to walk if the Teamsters and UPS can't reach a deal. The labor dispute could lead to the largest strike in U.S. history against a single employer and cause massive disruption in the shipping industry and beyond. Stephanie Sy reports on how the battle lines are being drawn. PBS NewsHour is supported by - https://www.pbs.org/newshour/about/funders
