He probably considers it one of his worst mistakes.
Now I see McInsane as one of the Swamp rats that is lining his pockets with money from lobbyist for the defense contractors. If you watch him, you can tell he wants a military mission to enrich the defense industry. McInsane is not bright enough to hide his bias like he could in his younger days. President Trump has triggered him to go into hysteria mode as he sees his gravy train coming to an end. This has destroyed his chameleon effort to hide his true identity as an influence peddler for the military industry.
Well, this would be a reason for him to ALLY with Trump, because Trump wants to beef up the military.
Yeah, he probably wasn’t counting on such a strong Sarah. He misunderestimated her, even though she was the force that brought his ticket as close to winning as it got.
But about allying with Trump... McCain is not a real hawk. He’s a forever conflicted soul trying to be half hawk half dove in a confused and self-contradictory manner.