“There’s a view,” he said, “that a reason for coming here is not to get something done but to prevent anything from getting done.” He cited the standoff on a budget resolution: Republicans beat up on Senate Democrats for years for failing to pass a budget, and now that the Senate has finally passed a budget, Republicans are objecting to the Senate naming conferees to negotiate a budget with the House.

He’s also got a problem with the roughly 15 isolationists in the Senate GOP caucus, a few of whom earned his famous “wacko birds” label. McCain claims he borrowed the phrase from the Wall Street Journal — “not that I disagreed with it.”

Many on the left won’t forgive McCain his trespasses in 2008 and 2010, and many on the right won’t forgive what he did before and since. But McCain has arguably turned himself into the most important legislator in a generation, at the center of the debate on war, terrorism, spending, corruption, health care and just about everything else. Last week, McCain met for two hours with Obama and Vice President Biden on security matters; Monday morning, he had a tete-a-tete with Secretary of State John Kerry.