“I know that he and other senators — and I’ve talked to a number of senators — are concerned about a growing isolationist wing within our caucus in the House and the Senate and in our party in general, which gets away from roots that we have in our party,” Weaver says…

But there’s something else to the fight beyond policy disagreements. “Some of it comes down to style differences. Perhaps it’s a maverick seeing another maverick — you know, generationally,” Weaver says, referring to Cruz. “I don’t know. I think most of it is policy driven.”

“McCain is one of the few senators who relishes the battle and isn’t afraid of a fight. The same could probably be said of Cruz, so we’re seeing some fireworks on the floor,” a McCain aide says, while dismissing as “nonsense” the notion that Cruz is a fellow maverick.

Even people one might normally find on Team McCain are a little unsettled by how pitched the battle has become. Senator Lindsey Graham, McCain’s best friend in the Senate, has joined with some of the wacko birds on various bills and letters, for example.