If McCain is reelected he will stab Brewer and everyone else who endorsed him at the drop of a hat. McCain will be 80 years old when he begins his next term. The likelihood of him being physically able to run for reelection in 2022, and serve for another six years, is low. McCain almost certainly knows this will be his last election campaign. Once he takes his seat in January 2017 the old self proclaimed maverick will not be accountable to the voters anymore. Who knows what he will do then.
Quid pro quo? Had NO idea Brewer was now part of the treasonous wing of the GOPe.