John McCain himself has been an ardent obstructionist and underminer of all things Trump.  When the president indicated McCain was not the hero he would admire, McCain has been obstinate and contrary ever since.  It is personal and not even political.  Collins, Graham and Murkowski are in the same boat.  Several of the above sunk the rather weak Obamacare repeal, despite having voted for it many times before.  They should get with the program, or go back home to their respective states.