So who is the real McCain?
There's the national security expert pounding the Obama administration with words like "cover-up" and "incompetence" over the deadly assault in Libya last September, snarling about the administration's lack of backbone on Syria and ripping into Defense Secretary nominee Chuck Hagel over the Iraq war.
But there's also the Arizona lawmaker reviving his past bipartisan effort on immigration by reaching out to Obama, the man who beat him for the presidency in 2008, as well as several Senate Democrats. Frustrated with the endless cycle of fiscal crises, McCain recently was part of a small group of GOP senators to talk budget at a dinner with the president.
In the first months of the year, McCain as friend or foe has given Washington whiplash. The swings seem even more pronounced as the 76-year-old lawmaker, perhaps in his last term, relishes more independence while Obama, also unencumbered electorally, pursues an ambitious second-term agenda.
The white-haired, fast-moving McCain—presidential candidate in 2000 and 2008, and congressman and senator for some three decades—insists that he has been consistent all along, working with any president while being outspoken when he has differences with the nation's leader.
"I will always do what I think is right whether it be Republican or Democrat president," McCain said in a recent interview in his Capitol Hill office.
He quickly adds: "When I disagreed with George Bush on what was happening in Iraq and said (Defense Secretary Donald) Rumsfeld ought to be fired and advocated a surge and voted against Medicare part D, it was the brave maverick standing up against George Bush. When I disagree with Barack Obama on Syria, Libya and other issues, it's the grumpy old man, angry old man."
McCain said that description is the furthest from the truth.
"The last thing I am is bitter and angry. ...I've had the most full life. I would compare my life to anybody that I've ever known and it's been one of great good fortune and I'm grateful every day," said McCain.
He later ticks off a lifetime of near-death experiences—surviving the July 1967 fire and explosion on the USS Forrestal that killed 134 sailors, flying into power lines in Spain, the October 1967 shoot down of his Navy aircraft and fall into Truc Bach Lake in Hanoi and 5 1/2 years in a North Vietnamese prison.
Whether confrontational or conciliatory, one thing is clear: McCain is ubiquitous, front and center on nearly every issue.
He's challenged some members of Obama's national security team—U.N. Ambassador Susan Rice and Hagel—while delivering a full-throated endorsement of his friend, Secretary of State John Kerry. He's tangled with the tea party wing of the Republican Party over cuts to defense spending and the administration's use of drones in the war on terror. He's called for an overhaul of the nation's immigration system with a path to citizenship for the 11 million illegal immigrants. He's a mainstay on the Sunday talk shows.
"He's easily bored," joked Sen. Lindsey Graham, R-S.C., McCain's ever-present friend and ally.
Former McCain aides, always loyal to the boss, point to a confluence of issues this year that have always been the senator's expertise, from national security to immigration. Democrats observe that Senate Minority Leader Mitch McConnell, R-Ky., and the GOP's No. 2, Sen. John Cornyn of Texas, face the constraints of re-election races next year and the need to protect their right flank from a tea party challenge.
That creates an opening for McCain, the Senate GOP's version of a free agent.
"His independence gives him more credibility really within the caucus and I think outside the caucus," said Sen. Lamar Alexander, R-Tenn. "Plus he's no shrinking violet, so he doesn't mind saying what he thinks."
McCain is a throwback to another Arizona Republican who pursued the presidency in 1964, suffered a bitter rejection and then returned to the Senate to compile a list of accomplishments. Fittingly, McCain's office is a testament to a unique political symmetry with Barry Goldwater.
McCain uses Goldwater's desk and in the back corner of his office is a series of black-and-white photographs of Navajo Indians that Goldwater took in the 1930s. Other photos and documents are a reminder of McCain's work with Democrats, particularly the late Sen. Ted Kennedy, D-Mass.
It's that type of bipartisanship that's in vogue again.
McCain is involved in negotiations with a group of eight Republicans and Democrats on immigration, including Dick Durbin, Chuck Schumer, Marco Rubio and Graham, and describes himself as "guardedly optimistic" about working out a deal. He and Graham met with Obama at the White House two weeks ago.
"He's willing to give us a shot at it," McCain said of Obama. "I think he wants a bipartisan solution the same way Bush wanted Kennedy and I to come forward."
Political divisions within the Republican ranks scuttled McCain-Kennedy efforts on immigration in 2005 and then again in 2007 in the lead-up to the presidential election. Even McCain, pressured by the GOP presidential primaries, spent more time talking border security than citizenship.
This year, after Hispanics overwhelmingly backed Obama and Democrats in the 2012 election, the GOP recognized it had a major problem.
"As far as Republicans are concerned I think there's a growing realization that the only way we can get on a level playing field for our Hispanic constituents is to get this done," McCain said.
He said he had a middle-of-the-night thought about the bill's name.
"If we ever pass this immigration reform, we should name it after Ted. He certainly devoted a hell a lot of his blood and sweat," McCain said.
On a crowded wall in a room outside his office, McCain finds a framed cover from National Review with a photograph of himself and Kennedy from past immigration fights and a personal note from the Democrat. He fondly remembers Kennedy's style, which sounds a lot like McCain's.
"Do I fight? Do I enjoy it in the arena? Hell yeah, but that doesn't mean that I'm angry. It means that I like to go in and do battle with them. My favorite was Ted Kennedy. We would go face to face. One time we were right at each other, and then walked off the floor and Ted said, 'we did pretty good, didn't we?'"
How much longer McCain keeps fighting in the Senate is uncertain. He is up for re-election in 2016 when he'll be 80 years old and says he does not want to overstay. His mother Roberta turned 101 last month and McCain jokes that based on her standards, he's just getting started.
"What I would do in a couple of years is go around, talk to people, the usual machinations," he said of a possible re-election bid, quickly adding: "I do not want to stay too long as I've seen some former colleagues."
Many of the old gang is gone. Kennedy died in 2009. McCain's best buddy, Joe Lieberman, retired from the Senate last year. McCain still talks about how the Democrat-turned-independent might have been his running mate in 2008 if it weren't for his support for abortion rights that never would have been accepted by the Republican Party.
"I miss him every day," McCain says.
Donna Cassata can be followed on Twitter at http://www.twitter.com/DonnaCassataAP