The most striking aspect of this HBO production (whose subtitle comes from McCain's favorite book, the Ernest Hemingway novel, and arrives along with a new memoir) is McCain's serenity as he reflects on what he describes as "an honorable life," for which he expresses gratitude."I love life, and I want to stay around forever," he says. "But I also feel that there's a great honor that you can die with."Of course, the signature period in McCain's early biography — his time as a prisoner of war during Vietnam — hardly smacks of good fortune, including the 2 ½ years that he spent in solitary confinement, being subjected to abuse and torture.Very little of this is new to those who have followed McCain, also profiled in a recent "Frontline" documentary. But it's McCain's own memories, coupled with the first-person testimonials, which elevate this to a higher level.The latter showcase the friends that McCain has made — among them Joe Biden, Joe Lieberman and Lindsey Graham — but also the admiration he has won from political rivals. Both McCain and George W. Bush discuss their bruising 2000 primary battle without rancor — despite the dirty tricks that took place — just as Barack Obama lauds McCain for resisting the temptation and pressure to inject race into their campaign.In what amounts to his closing arguments, McCain has already made headlines by expressing regret about selecting Sarah Palin, as opposed to Lieberman, as his running mate in 2008, a point he echoes here. If there's a quibble one can register against Kunhardt's presentation, it's that the film doesn't challenge its subject enough for his role in perpetuating the current partisan divide, despite recent high-minded rhetoric on the topic.The documentary certainly isn't a whitewashing, devoting considerable time to the Keating Five scandal, which threatened McCain's Senate career and informed his push for campaign-finance reform. But it also delves into McCain's maverick image, from the "Straight Talk Express" during his presidential run to his willingness to break with Republican Party orthodoxy, suggesting that some of his greatest failures stemmed from moments where he acted in the name of political expediency, compromising his own ideals.Peacefully walking the dog at his Arizona home and interviewed in that tranquil setting, McCain discusses how fortunate he's been. For a man who takes understandable pride in having weathered decades in the public arena on his own terms, "For Whom the Bell Tolls" clearly demonstrates his desire to leave on them as well."John McCain: For Whom the Bell Tolls" premieres May 28 at 8 p.m. on HBO.