It will be interesting to see how mainstream republicans react to a Trump nomination if Marco doesn't save it.
"Mainstream Republicans" are supporting Trump. The opposition is made up of fringe evangelicals, libertarian basement dwellers, and Beltway hacks who don't want to lose their cushy think tank gigs.
The Trump Deniers just won't go away.
The highlighted quote is why Trump is in such a commanding position. TRUMP is the Republican mainstream these days, moreso than the "Movement Conservatives" who thought they had the race locked up.