The Senate advanced legislation Tuesday that seeks to force President Donald Trump to withdraw from the Iran war, as a growing number of Republicans defied the president's direction on a conflict that has spanned well over two months. Since Trump ordered the attack on Iran at the end of February, Democrats have forced repeated votes on war powers resolutions that would require him either to gain congressional approval or withdraw U.S. troops. Republicans had been able to muster the votes to reject those proposals, but Louisiana Sen. Bill Cassidy — fresh off a primary election loss in which Trump endorsed his opponent — switched sides.