Oct. 27, 2011  -- On May 1, when President Obama announced that U.S. forces had captured and killed Osama bin Laden, Alex Gansa had what might be described as a minor panic attack.

"We were actually quite worried for a while," said Gansa, the co-creator and co-executive producer of "Homeland." "We had no idea that there was still an appetite to talk about these issues, to talk about the war on terror, to talk about how America was protecting its power overseas. Were people exhausted, was there fatigue? After bin Laden was killed, we were like, 'Well now everyone is really going to tune out.'"

Not at all. Showtime's "Homeland" is, by many accounts, the most riveting new drama of the fall season, winning critical acclaim and high ratings with its tumultuous tale of a mentally ill CIA agent (Claire Danes) hunting down a former POW (Damian Lewis) who she believes has been "turned" by al Qaeda operatives.

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In "Homeland's" universe, the men and women tasked with keeping our country safe drink heavily, pop pills and view sex as part of the job. Terrorists have succeeded in capturing a Marine sergeant, keeping him in a hole for eight years and converting the church-going dad into an Allah worshipper, if not an undercover terrorist too.

Lewis, the British actor who plays Sgt. Nicholas Brody, finds himself "waiting for, I don't know, the hostility" that some viewers might hurl at him.

"There is no greater symbol of what it is to defend our freedom and defend our way of life than a U.S. Marine," Lewis said. "To see a U.S. Marine possibly undergoing a change of heart, a change of mind, a change of attitude, to have been challenged to a point where he questions his loyalties and replaces them with a different belief system, that's going to be controversial and it's going to be shocking for some people."

So is he? Or isn't he?

"Ultimately, we're trying to challenge the assumption that just because Brody's converted to Islam, he's a terrorist," said Gansa. "He reached out to religion because he had nothing else in the middle of this horrible experience. You're meant to swing back and forth."

Gansa and co-creator Howard Gordon developed "Homeland" as their own kind of challenge: Could they combine a psychological thriller with a post-9/11 plot? They worked together on "24," with Gordon as executive producer from 2006 until the series' 2010 end and Gansa as a writer/producer for "24's" final two seasons. Two years ago, while wrapping up "24," they came across the Israeli series "Hatufim" ("Prisoners of War") and started sketching out an American spin-off.

"We were hoping that all we would have to do is change the names -- from Haim to Nick," Gansa laughed. "It turned out to be a lot more complicated than that."

Gordon and Gansa crafted the show with a premium cable channel in mind. In Gansa's words, they elected to "embrace the ambiguity" of whether or not Brody has been turned and extend the same uncertainty to his foil, bipolar CIA agent Carrie Mathison.

"On one level, Alex and I, just as story tellers, wanted to find a character unlike Jack Bauer," Gordon said. "A woman who was younger who was in many ways very gifted and in many ways really broken, vulnerable and in need of mending."

Carrie breaks the law and flies into rages. She self-medicates with a handful of mood stabilizers, a slug of liquor, or both. A model spy she is not. A former CIA agent characterized "Homeland's" version as "highly inaccurate," but according to Gansa and Gordon, that's part of the point.

"We met with a number of former and current CIA agents, we read a lot of books, and we invented the rest," Gansa said. "We obviously wanted to be as true to life as we possibly could, but we would always err on the side of making the story more exciting and more thrilling."

They gunned for Danes from the start.

"We needed somebody by turns who could appear very confident and very unbalanced at the same time," Gansa said. "Claire was the first choice from the minute we started the character. We actually called the character Claire in the first couple of drafts."

Gansa said that aside from the 2010 HBO film "Temple Grandin," for which Danes won an Emmy, he and Gordon "just felt that she wasn't being served well by the projects she was involved in."

"We felt this was a chance for her to play something different," he said. "A real professional woman. Not the love interest, not the best friend -- a real strong, meaty, smart female character."

Danes declined to be interviewed for this story through her representative. She and the rest of "Homeland's" cast and crew have been busy: Over the past week, they've descended on Charlotte, N.C., for what will likely be a 15-day shoot for the season finale. That episode, "Homeland's" 13th, will be longer than the usual hour, clocking in at 80 to 85 minutes. They hope the pattern extends to the series.

"We're in that beautiful little bubble that people kind of dream of when you've just launched a show, the critics raved about it, people seem to be watching it, and you just get the sense that this is the best it can ever be," Lewis said. "You just hope that the bubble won't burst."