McCain already has plenty of experience endorsing presidential candidates he dislikes.
John McCain made his name as a supposed maverick and Republican truth-teller, but he's telling a deeper truth about who he is when he answers the question of
whether he'd support Donald Trump for president in 2016:
“It’s hard to predict because a lot of things happen between now and then but I certainly would support the nominee, no matter who it is,” said Sen. John McCain (Ariz.), the 2008 GOP nominee whose war record and imprisonment in Vietnam was mocked over the summer by Trump.
Remember back in July when
McCain said Trump had "fired up the crazies" on immigration, and a few days later, Trump's campaign was
supposed to be over because he said McCain was "not a war hero" and "was a war hero because he was captured. I like people who weren’t captured"? Water under the bridge, if Trump locks down the Republican nomination. At that point, McCain will give him the hug of seething shame and resentment we saw him give George W. Bush so many times and will be the non-mavericky good Republican soldier he is in his heart (and really, everywhere but in the eyes of beltway political reporters).
Or maybe he's lost that sense of shame—after all, he gladly supported Sarah Palin.