Sen. Bob Menendez of New Jersey has vowed he's not going anywhere amid a federal corruption case against him, but the party he once held considerable sway over is looking beyond him. Party leaders, from Democratic Gov. Phil Murphy to local officials, have called on Menendez to resign. His home county party has dropped its endorsement, and in a year when Democrats will be fighting to preserve their slim U.S. Senate majority, a field of robust primary challengers has emerged in traditionally Democratic New Jersey. U.S. Rep. Andy Kim entered the day after the indictment. The state’s first lady, Tammy Murphy, has begun to win significant support from county party officials.