There are 316 million people in the United States of America. About six million of them watch 'Homeland,' Showtime's thriller about world terror, paranoia, and bipolar disorder. That's about 2 percent of the population; roughly what the guy with the beard running on the Libertarian Party ticket gets when he runs for Congress.

But it's the right 2 percent. It includes CIA analysts, spooks, and at least two United States presidents – something 'Eastbound & Down' can't claim.

Two percent love is how Damian Lewis, who plays Marine–quadruple agent–Muslim convert Nicholas Brody, found himself shaking Barack Obama's hand last year before a White House state dinner with British prime minister David Cameron. Resplendent in a tux, Lewis led with a joke.

"Mr. President," he said, "the writers had asked me to say, if we're going to go into Iran, would you give us a heads-up, because we'd like to keep the show as current as possible."

"That's enough," he told Lewis. "Move down the line, sir."

He did as he was told.

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Lewis thought that was it, so he was a bit surprised when he was ushered to his seat for dinner and the guy across from him was the president. They made small talk about what a fanboy Obama was before Lewis asked him a question that had been nagging him all evening: How the hell did he find time to watch Homeland?

Lewis, whose red hair is buzz-cut short, tells the story well, slipping into a better-than-SNL Obama imitation.

"Well, Damian, on Saturday afternoons, Michelle takes the girls to play tennis, and I say I'm going to the Oval Office to work, and instead I watch 'Homeland.' "

Everyone had a good laugh. After the dinner, Lewis cheekily signed a DVD for the president: "Mr. President: From one Muslim to another."

A week passed. Lewis started getting nervous.

"I panicked after I wrote that," says Lewis. He arches his auburn eyebrows for comic impact. "So, a week later I wrote [White House press secretary] Jay Carney, whom I'd become friendly with." (I told you the show was connected.) "I said, 'Hi, Jay; I hope the president liked my present and has a sense of humor.' Jay wrote back and said it was totally cool and he loved it."

International incident avoided! (Lewis' encounter with Bill Clinton was less risky, if longer-winded. The former president gave Lewis the two-handed handshake and went into a Clintonian monologue about the importance of the liberal view on the consequences of terrorism being represented in popular culture. Lewis nodded a lot.)

But it's not presidents who hold Damian Lewis' future in their hands. That would be the 'Homeland' writers. It is the morning after the show announced to the Television Critics Association that Lewis, the man who just won an Emmy playing Brody, would be MIA from season three's first two episodes.

"With Brody, I feel like I'm on a stay of execution with each episode," says Lewis, scarfing a three-egg omelet in L.A. before a flight east to the 'Homeland' set in Charlotte, North Carolina.

He's not joking. Homeland's co-creator Alex Gansa keeps Lewis apprised as to whether Brody is still breathing on a weekly basis. It's a day-by-day existence that you can't imagine James Gandolfini or Jon Hamm living with during his show's heyday. The weird thing is the only guy who doesn't seem to care if Nick Brody comes or goes is Damian Lewis.

He has his reasons.Now 42, Damian Lewis has played two of the most indelible soldiers in the history of American television. First it was Dick Winters, the stoic hero of HBO's 'Band of Brothers,' and now Brody, a Marine sniper held for eight years by Al Qaeda before returning home. Brody's public image is superficially all-American; his motivations are instantly questioned by an unstable-CIA-agent-off-her-meds blonde played by Claire Danes, who thinks he is a lethal terrorist. (Their adversarial roles don't preclude the two from fucking each other's brains out now and then.) Lewis' actorly transition from Winters to Brody is a televised look at a country saying goodbye to the Greatest Generation and hello to the Paranoid Generation.

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The great cosmic joke is that the man leading us through America's twilight is British. And when I say he's British, I mean he is bloody British. His grandfather was Lord Mayor of London, a ceremonial but influential position. His sister worked for Prince Charles. He grew up near Abbey Road and went to Ashdown House, a boarding school near where A.A. Milne set Winnie-the-Pooh. Lewis and his chums would go to Pooh Corner and toss Poohsticks. I'm not making this up.

Lewis then went on to Eton, a 573-year-old British boarding school that has produced 19 prime ministers and one George Orwell. He appeared in five Gilbert and Sullivan musicals by 13. He is not immune from slipping into aristocrat lingo. When he mentions that he wants to direct one day, he quotes fellow Etonian buddy Dominic West, of 'The Wire' fame: "Oh, darling! The power! The power." I had to check to make sure that wasn't a paraphrase from an Evelyn Waugh novel.

Maybe the trips to Pooh Land and Eton sound like an idyllic childhood, but they didn't come without moments of cruelty and ass-clenching terror. "I was caned – they still caned back in the 1980s," says Lewis matter-of-factly. (A cricket bat once was broken on the backside of a classmate.) His father traveled through the Middle East for much of his youth. Eventually, Damian and his younger brother, Gareth, told their mom she should stop her regular Sunday visits to school.

"It was kind of weird just having your mom appear, just be with you for an afternoon," says Lewis at Hollywood's Chateau Marmont, the ultimate signpost that the Etonian was now an American star. "You had to try to cram all your experience into an afternoon with your mother, who was desperate to know everything. And then you'd be saying goodbye to your mum again before you went back to school, into a dormitory, into a sort of Dickensian setting."

The fact that Lewis is so posh makes his turns as quintessential Americans Winters and Brody all the more remarkable. And his note to Obama suggests he's not the English gentleman in the bowler hat catching the 5:15 back to the home counties. He's a likable bloke with a wicked sense of self-deprecating humor. I ran into him in the boarding line at LAX as we both headed to the Homeland set in Charlotte. He was wearing a blue newsboy cap and T-shirt. There was no ascot.

I mentioned that I was downloading 'The Baker,' a comedy Lewis starred in, directed by his brother, Gareth, and grievously renamed 'Assassin in Love' for the American market. Lewis just laughed. "Someone else I know is watching it, so that will make five in America."

Lewis settled into a window seat in first class and was quickly joined a row behind by a harried blonde rassling with a baby. It was his co-star, Claire Danes. For much of the flight's five hours, Lewis ignored the chatty Hollywood executive next to him and spun around in his seat making googly eyes at six-month-old Cyrus while shooting the shit with British actor Hugh Dancy, Danes' husband. It wasn't an accident: Dancy is between shoots for 'Hannibal' and has been spending a lot of time playing house daddy in Charlotte; spouses on a set can feel like they're never in on the inside jokes. Lewis wanted him to know he was welcome and that, uh, things between him and Danes were strictly professional.

"I take it very seriously if someone's husband is coming into a situation where his wife is doing intimate work with another man," Lewis told me the next day. "I go out of my way to make friends and to reassure him he has nothing to worry about. That just seems to me like a good common courtesy."

Hey, I said he was a likable bloke – that doesn't mean he isn't still freakin' British.The next day, I met Lewis on Homeland's set, where he had to knock out some promos for season three. It was his first visit in a month, and the boards in the production office mapped out scenes for a midseason episode, including a mysterious one labeled "At the murder house." Lewis had been gone a month, was leaving the next day, and wasn't scheduled back in Charlotte for a few weeks, suggesting his screen time in season three will be truncated.

The staff was happy to see him, gleefully pulling up tabloid photos of a bald Lewis arriving in a blue Jaguar on the Scottish island of Mull, where he was filming 'The Silent Storm' – Lewis plays a married minister embroiled in a love triangle – on his Homeland break.

Someone asked him if he was bald in the movie.

"It was fine until they put a wig on me, like Pierce Brosnan in a hairpiece," says Lewis, shaking his head. "They tried to age me up, so I had silver flecks going through it. I sort of looked like Blake Carrington."

Lewis' constant taking the piss makes his transformation into the darker-than-dark Brody all the more impressive. For the uninitiated, here's a quick primer. Brody – as everyone, even his wife, calls him – is a Marine sniper captured along with a fellow sniper by the Iraqis, who sell them off to Al Qaeda. Brody spends the next eight years being tortured and is forced to beat his fellow sniper to death and then bury him. (Or at least he thinks he does! It's complicated.) He is then befriended by one of his captors, Abu Nazir, a Bin Laden–like figure who nurses him back to health and then has him teach English to his son, Issa. Brody falls in love with Issa, a replacement for his own two children back in America. He converts to Islam. But then Issa is killed by an off-the-books American drone strike. An enraged Brody is then set free by Abu Nazir. He is left where he will be found by American soldiers and is returned home as a hero but with secret revenge for Issa on his mind.

And that's just season one.

It's Lewis' Brody who keeps the crazy train moving down the tracks. While Danes' manic Carrie can teeter on 'Rain Man' parody, Brody seems real and vulnerable no matter how insane the plot veers. There's a key scene in season one where television crews surround Brody's house while his family is at work and school. All alone, Brody goes into his bedroom and slips into the fetal position in the corner, just like he used to do in his prison cell. Many actors would be tempted to throw in twitches and flashes of the crazy eyes, but Lewis manages to convey pure terror and sadness without the fireworks.

Lewis shows me around the Brody house – "The real house where we shoot the exteriors smells of cat urine" – and we walk into the bedroom. At first Lewis tries to slough off the scene.

"I always enjoy saying I give it up and it's gone," says Lewis. "I find it difficult to remember what I did the next day. I'm naturally lazy."

I tell him this sounds like the Eton equivalent of Harvard grads claiming they wrote their thesis while drunk and in drag backstage at the Hasty Pudding production. Lewis' face reddens.

"You spend a lot of time perfecting that image; there's no question you do," says Lewis. "It's vulgar in some way to appear like you're trying too hard. It's somehow inelegant. I suffered from that definitely, but I don't mind people watching me work hard now. That is something I've consciously changed."

He starts talking again about the Brody fetal-position scene. Before shooting, there is usually a tech rehearsal of a scene where lighting and sound are checked. Usually, this is done with stand-ins, but Lewis likes to participate.

"We're always encouraged to get out so everyone can work and the lighting can get done," Lewis explains, "but I sometimes like to stay in the space. The more I can do that, the more it sits in you, the more prepared you are."

Lewis spent much time researching the effect of prolonged captivity and PTSD on returning soldiers and hostages, particularly by reading Brian Keenan's book 'An Evil Cradling,' about his four years of captivity in Lebanon in the 1980s.

"With PTSD, there's a disconnect between – and this is actually the definition of any kind of trauma, whether you've been abused at home, raped, beaten, whatever it is – your experience and the ability of your mind to file it, recognize it, and analyze it," says Lewis. "You're frozen by it. And there's a sense of injustice that no one can really understand what you've been through, so you feel entitled to behave in any way you want, and if that means setting a car on fire out of anger, you feel justified. That's where Brody is."We head out for lunch, and Lewis slips back into life-is-a-pint-of-Guinness mode. "I stay in my American accent all day. You know, I never did have a dialect coach when I played Dick Winters," he says. "It was just plausible."

Lewis was already a stage star in London when he was asked to read for 'Band of Brothers.' He auditioned for months and months. Then the casting director called and asked if he would fly to Los Angeles to meet with the show's producers. He did another reading, thought he was done, and proceeded to stay out in L.A. until 4 am.

The phone rang a couple of hours later, and Lewis was requested to meet Steven Spielberg at his office at 8 am. After a pot of coffee and multiple showers, a still-soused Lewis made it to his appointment. "I was still drunk," he says. "I was sweaty palmed and shaking when I went in." Spielberg congratulated him on being cast as the lead.

Lewis' portrayal of Winters scored him a Golden Globe nomination, but he inexplicably lost to James Franco playing James Dean. The entire experience was simultaneously breathtaking and heartbreaking – Lewis' mother was killed in a car accident in India while 'Band of Brothers' was in post-production. "She was a real tiger mum in some ways; I wanted to dedicate the Golden Globe to her," says Lewis, who took home both a Globe and an Emmy for the Brody role. "I just had to wait 10 years."

Lewis has tried not to let any false moments creep into Brody, though 'Homeland' has already taken a sharp left turn because of his popularity. Originally, season one was supposed to end with Brody detonating a vest bomb, killing himself, the vice president, and his advisers.

The relationship between Brody and Carrie proved wildly popular with fans, and at the last minute, the show had Brody chicken out, not detonate the bomb, and live to fight for another television season.

"I think simply for creative and artistic reasons, the writers want to kill me," says Lewis. He speaks frankly, as if the CIA has just poisoned his OJ with truth serum. (That totally could be a plot twist this year.) "There are so many compelling and devastating story lines that would just be great TV and theater," says Lewis with a smile. "The more compromised storytelling is to keep him alive and to keep him bubbling along somehow. It's the executives who write that version."Those same executives vowed Damian Lewis would never play Brody. Back in 2010, Danes had already been cast as the female lead. But finding her foil was proving difficult. "It was really hard because you needed an actor who could play a cipher in the first few episodes," says 'Homeland' co-creator Alex Gansa. "Actors always want to make a choice: My guy is a bad guy; my guy is a good guy. I really thought Damian could pull off not going either way."

But the studio didn't agree. Gansa went back to work and found a guy, but Danes exercised her veto power. So he went back to the studio with Lewis' name again. Their reaction was not positive.

"They told me, 'I never want to hear that name again; Damian Lewis is a dead issue,'" says Gansa, chuckling. The show was in danger of being stillborn when Michael Cuesta – director of the show's pilot episode – told Gansa about a barely seen 2004 indie film starring Lewis.

The film is called 'Keane,' and it follows Lewis in some state of psychotic breakdown as he wanders around Port Authority looking for a lost daughter who may or may not exist. It's 90 minutes of the most harrowing film I've ever seen.

Fortunately for Lewis, Keane was available for streaming immediately on Netflix. "I can guarantee you that if it wasn't streamable, I wouldn't have watched it," says Gansa. "We got it to the studio, and the network watched it that evening."

Keane changed everyone's mind. Only Lewis needed convincing.

He spent much of his 20s doing Shakespeare in both London and New York. He never felt the American itch. (Even Band of Brothers was filmed in England.) He made a good living on British television and met his wife, Helen McCrory, a British actress, in 2003. They were married in 2007 and had two kids, Manon and Gulliver; the domestic life he never had as a child was right there.

But then Hollywood called. It was for an NBC show called 'Life,' in which Lewis played a semi-nutty detective back on the streets after serving 12 years in prison on a trumped-up charge. Lewis loved the writing and saw it as a great adventure for the family, and they moved to Santa Monica. The show won awards, and Lewis' performance was praised to the heavens.

There was just one problem: Lewis was working long days. The show creator promised him a B story that would give him more time to spend with his wife and kids, but it never happened. He had an agreement with McCrory – who was in the last three 'Harry Potter' films – that they'd alternate whose career received priority, but Life was all-consuming. If you look at pictures of Lewis at the time, he already had the hunted, gaunt look of Brody down. He suspected he had a virus or something similar, but he simply didn't have time to go to the doctor. After two seasons, Life was canceled so Jay Leno could start his disastrous 10 pm experiment. It was a sort of blessing.

"Helen was stuck with two small children, and I was working 70 hours a week in the Valley," says Lewis. "It was a lot to handle. And we were determined to have a social life, so weekends became extremely active. We went to Twentynine Palms or just made sure we had a great evening. We saw people and threw dinner parties." Lewis laughs. "Come to think of it, I think that's why I got sick."

When 'Homeland' came calling, the idea of moving the family – now reestablished in London – to North Carolina or leaving them back in England weighed heavily on Lewis. In the end, he said yes.

"The problem was the script was so good," says Lewis. "I didn't want to play the upstanding American man. But that's not what they wanted to do. There's no Gary Cooper on the show."

But the question remained whether he would have real chemistry with Danes. It wasn't magic from the start. Danes and Lewis' first scene was a group interrogation after Brody is repatriated. The scene was so flat everyone agreed it needed to be reshot. It wasn't until their next scene that things clicked into place. Carrie ambushes Brody at a veterans support meeting – acting like it was a mere coincidence – and they have a short conversation about how difficult it is to talk about "over there" with people back home. There's a moment where Danes and Lewis both flash electric smiles of recognition. Gansa was back in Los Angeles, where the Homeland writing room is located, when his assistant told him he needed to watch the dailies as soon as possible.

"I asked, 'Is it bad?' " Gansa recalls, laughing. Quite the contrary, she told him. "That's when we knew we had something with Claire and Damian."

But how long will it last? Gansa admits to giving Lewis weekly updates. "I think Damian probably has two minds about it. It's been three seasons, he's won a Golden Globe, he's won an Emmy – is it time to move on to something else? He may feel that way. I don't know. At some point, that Carrie-Brody relationship is just going to be exhausted. And the show will morph into something else."

While Lewis is happy to argue both sides of whether Brody should live or die, he won't cop to a preference. We rode to lunch near his Charlotte residence, and he busily texted his wife and kids. "I'll just see what happens," said Lewis. He sounded most Brody-like.One thing does come through with Lewis that may make the death of Nick Brody more acceptable: He misses his wife and kids desperately. They usually come over for a month or two and enjoy the run of the apartment where Lewis stays while filming. He's cut back on golfing and now seeks out more family pursuits like hiking in the Smoky Mountains. "My kids think America is swimming pools on the roof, screening rooms, and hot dogs," says Lewis. "They love it here."

But his kids are going into school now, making Charlotte time more tenuous. He says he's going to break family tradition and keep his two children at home. While Lewis extols his boarding school experiences – the plays, the cricket, the camaraderie – he knows its dark side.

"Do I think an eight-year-old should be put through that sort of sphincter exercise that I was? Where you're just having to hold on because if you don't, you could just weep? I know the answer is no."

For the first time, I see the vulnerability of Brody in Lewis' face.

Sure, he spent his youth at Pooh Corner and cavorting with future prime ministers, but to leave home at eight is a gilded 'Lord of the Flies' childhood with bouts of loneliness. He doesn't want to inflict that on his kids – he talks dreamily of a ramshackle house with a dog and Sunday dinners – but in reality, he is half a world away, still scratching around in Brody's hole, the role of a lifetime maybe coming at the wrong time.

It reminded me of our first conversation back in Hollywood. A couple of fans came over to shake his hand, but Lewis was preoccupied with talking about his kids.

"You live with the burden of being gone, that guilt, for the rest of your life," says Lewis, his hail-fellow-well-met face going a little flat. "And you will rationalize it in all kinds of ways, and I'm really proud that my son and daughter can see that Dad's working hard, making success at what he does. You actually have concrete things you can show them."

Back in Charlotte, we say goodbye on a busy street, but not before he gives my cabbie extensive instructions on the best route back to the Homeland set. Lewis has some calls to make about a film he's hoping to direct, but more important, he wants to Skype with his kids before they go to sleep. Tomorrow a nonstop wings him back home and he starts a family vacation on Ibiza. In the end, Brody and Lewis have one specific thing in common: When they're not killing vice presidents or meeting real presidents, they both have two kids and they both want to make sure they're OK.

The clock is ticking.

Stephen Rodrick wrote the cover story on Keith Richards in the July 2013 issue.