The White House is monitoring contract negotiations between auto workers and Detroit’s Big Three automakers. The UAW contract expires at midnight and workers have authorized a strike if there’s no new agreement. President Biden has a record of backing unions and collective bargaining. But the White House is not saying whether the president would support striking workers or whether he might step in to try and head off a strike. Officials say Mr. Biden has encouraged the parties “to stay at the table and to work 24/7 to get a win-win agreement.”