NEW YORK — When he made his way into the director’s chair for a new phase in his career, Ben Affleck always assumed that if he came across an existing script, he would likely just take over and re-write it. And of course, he has the credentials: an Oscar for co-writing “Good Will Hunting” with Matt Damon goes a long way toward legitimizing his talent as a writer. But when “Argo” was fired across his bow by Smoke House honchos Grant Heslov and George Clooney, that wasn’t the case.

“I said, ‘Look, I think the script is kind of close to perfect and I”m just going to do it,'” he recalls alongside screenwriter Chris Terrio after a well-timed, Academy member-attended luncheon at the Four Seasons Restaurant. “I will never have a script that’s this close to just, ‘I”ll shoot it today.’ I remember telling my agent that; I was like, ‘We could shoot this tomorrow. It’s basically finished.’ And I doubt that will happen again. It”s just so rare.”

Terrio had picked up the assignment through Smoke House after an article in Wired Magazine sparked interest. What was intriguing to him was that it was an opportunity to put “almost this shameful taboo” of Iran back on the table as a topic of conversation. It had a bearing on the zeitgeist, but there had been a kind of curtain that descended on Iran after the 1979 Iran Hostage Crisis, he says, not just because of the extremist government but even in the national conversation about it. He felt this material brought those elements back out.

“The national conversation about Iran is always about nukes, about a crazy speech that Ahmadinejad makes at the U.N.,” Terrio says. “There isn”t a more considered discussion of the fact that we’re still in the same place that we were, diplomatically speaking, in 1980.”

But no one quite knew what the movie would be. Was it a comedy? It certainly had those elements. Was it something narratively or tonally complex, like “Syriana?” It wasn’t clear what approach to take. Terrio had an idea of the three worlds depicted in the story — that of the CIA in Washington, the lunacy of Hollywood and, of course, the exotic world of Iran — and so that’s the thematic structure he pitched.

“The other interesting thing about this story is that it’s a significant moment in news as well as a moment in history,” he said just an hour earlier to attendees of the luncheon in a Q&A that included Affleck, production designer Sharon Seymour, actor Victor Garber (who stars as Canadian ambassador Ken Taylor in the film) and real-life hero Tony Mendez (who Affleck plays in the film). “That is to say, satellite technology was new and suddenly these images are being beamed all over the world instantly. So it was important for us that things like the televisions that are constantly on in the film, it was more than just ways of sneaking in exposition. It was important that in the DNA of this story should be ways in which the story is told, and the representation of this story, because the students in Iran know that they’re telling the story. They know that these images that they’re putting in front of the cameras are being beamed all over the world. That began to resonate with the Hollywood stuff, which is not only understanding historical context but understanding the way that it’s represented. And in fact, the way they’re representing history creates history.”

It was a wide-ranging sort of story that demanded some tinkering in order to bring it in as a movie. The places where Terrio composited or changed anything were purely for those purposes, he says, for narrative compression and allowing the story to deliver in two hours. The stew itself was broad and all-encompassing, so the “sins of omission” were felt more than anything.

“Because pretty much any topic that we were interested in is in someway encompassed in this story,” he says. “It touches upon all these worlds in quite a natural way. I mean, we weren’t extending octopus tentacles to get ourselves into a discussion about Carter in the primary in the White House. That was a real thing that was going on at the time with Hamilton Jordan. We weren”t extending tentacles to be able to stage the juxtaposition of press conferences in Hollywood and in Iran. All these images that are in the film are really things that were in the DNA of the story.”

So there were a lot of ideas bubbling in the pot and Terrio stirred them all together and came up with “Argo.” And in Affleck, Smoke House had found a director uniquely suited to the material.

Years ago, when he was living on Hill Street in Eagle Rock, just northeast of downtown Los Angeles, seeking out parts, toiling away on scripts (one of which, the aforementioned “Good Will Hunting,” would ignite his and Damon’s careers), Affleck attended Occidental College for a time. While there, he majored in Middle Eastern Studies, not all that popular at a time when others were taking Soviet studies and the like, aiming for political science jobs. His mother always wanted him to go to college, which was part of the drive, but he also felt that an educated actor or an educated director was bound to be better at his job.

“I was interested in it because I thought it was sort of unknowable, this mysterious place that is somehow at the root of so much conflict,” Affleck says. “And it was something that I didn”t understand. I had this immature notion that there was, you know, what is it, ‘flying carpets and snake charmers’ [a line from the film]. But once I got into it, I got really interested in it for whatever reason. And I felt like I had been sort of built by chance as being totally right for this movie because I am really interested in all these separate things.

“I’m also interested in the complexity of the idea that everybody has their reason, their side of the story. Palestine and Israel, that’s a place where you have two people with really diametrically opposed points of view. And yet both firmly believe they”re not just right but righteous. And that dynamic, I think, is at the root of drama. That”s why you never make a bad guy mustache-twisting. The bad guy thinks he”s in effect the good guy. Or at least he thinks he has good reasons for doing what he is doing. So I think that my attraction to drama, dramatic literature and doing theater and film can be related to what”s at the heart of studying Middle Eastern studies, at least for me.”

So with the right credentials and a “perfect” screenplay in place, it was off to make “Argo.” The mission was declassified by the government in 1997 and really made its way out via the Wired article 10 years later, so Mendez was available to consult, as well as five of the six “houseguests” who were rescued. And the CIA gave some nominal help, but how much? After all, as someone at the luncheon noted, there is a card at the end of the film that seemingly absolves the organization of cooperation.

“It says ‘The CIA doesn’t endorse this movie,’ essentially,” Affleck told the crowd. “Even though they granted us some degree of access, it’s their way of saying, ‘Don’t think that this represents our view in any way.’ They both accepted us and repudiated us, which I feel is very like the CIA.”

But while everything was clicking and looked great on paper, there were a few wrinkles Affleck needed to iron out. One of the key elements of the story is its shift in tone, from the sincere danger of the crisis in Iran to the seemingly satirical (if only it weren’t true) take on 1970s Hollywood. A colorful assortment permeated the latter, including a composite producer (played by Alan Arkin), who would help launch the faux-film “Argo” as cover for the operation, and Oscar-winning makeup artist John Chambers (John Goodman), who was a civilian CIA consultant.

“I thought they worked fluidly in the script, but of course, on paper, it’s kind of easier to mask some of the incongruities that may exist tonally or visually or what have you,” Affleck said during the luncheon. “So I was quite concerned. I constructed a lot of these transitions so as to hopefully kind of knit it together. And then what happened was when John and Alan showed up, the scenes didn’t feel funny in that comic way, ‘Ha, ha,’ or they didn’t feel funny in the way that you sort of say, ‘All right, we’re not going to take reality seriously.’ They felt like two people saying things that they would genuinely say.”

In both cases, he says choosing the actors for those roles was kind of a no-brainer. For starters, Arkin’s dry sense of humor and no-nonsense attitude seemed tailor-made for the producer, leading the actor to even joke with Affleck about the obvious nature of the casting decision. “He really has that aura of a guy who”s just done enough and accomplished enough,” Affleck says. “He knows himself well enough and is old enough where he just doesn”t care about impressing anybody or changing his behavior at all to meet other people”s expectations. And I think he enjoys that. He was kind of the ultimate choice.”

John Goodman, meanwhile, actually bears a physical resemblance to Chambers, which made that decision even easier. “When you look at the picture and you look at John, and you think of their sensibilities there and the movies they have done, I don”t know how much credit I should get for casting because it”s so obvious,” Affleck says. “It was just a question of getting them; it wasn”t a question of who it should be.”

In hammering out a visual look, Affleck concedes he stands on the shoulders of giants. Craftspeople like Seymour, who was tasked with steeping the film in period without calling overt attention to that, or DP Rodrigo Prieto, who would discuss at a post-screening Q&A a few days later the various film tests he went through to produce the distressed look that Affleck liked — they are a huge reason for the success of “Argo” on a visual level.

Affleck looked to films like “The Verdict” and “Three Days of the Condor” for cues, “The Parallax View” as well. And like another CIA film that’s hitting theaters this season, “Zero Dark Thirty,” “Argo” owes plenty to “All the President’s Men.”

“It was mentioned in the script and when I saw it mentioned in the script I really took it and kind of ran with it,” Affleck says of Alan J. Pakula’s 1976 film. “I looked at how it was shot and I learned a lot. There was a use of wide shots that was different. They used diopters to give the room more depth, which we did in a couple other scenes. They kind of kept the camera on a dolly for that stuff and I don”t know if that was intentional or not but I thought that would be a good counterweight to the handheld stuff for Iran. And I really liked the color palette and the way that it seemed to be very sort of expansive, even though it was interiors. And the acting was just magnificent.”

But for all the talk of formalism, it was important to Affleck that the film’s visuals always connect on a human level. While he and Terrio weren’t afraid of structure, they also wanted to leave the film room to breathe.

“Ben keeps bringing it back to this humanist thing where you just keep landing on the faces of people, whether they”re the actors or whether they”re the extras,” Terrio says. “And I think that when you’ve carefully thought out a structure, it”s important to keep finding the little messy edges, the places where the edges fray a bit. And I think Ben does that. Constantly, right up to the end, you never feel like you”re going through some sort of direct linear structure, because it keeps trying to elbow its way out in any number of scenes. Things like the bazaar, where it suddenly feels like this strange belly of the beast that you”re going into structurally, and yet when you”re watching the scene it just feels like this dynamic, alive organism.”

It was all part and parcel of creating a vast mixture that might seem on the surface to be simplistic or just straight-forward as a thriller, but underneath, has plenty on its mind.

“I feel that if you could encapsulate your movie in a sentence you probably shouldn”t make it,” Affleck says, “because why not just tell people? But for me, it”s dealing with themes and those themes, if done well, will provoke things in the audience and they take it from there. But, that being said, I do think it’s really interesting, politically speaking, to look at the fact that Iran is our greatest foreign policy concern right now and this is the root of that. I had never seen a movie that’s represented it so cleanly or wanted to deal with it so acutely. It also, I think, reminds people of what sort of connection we all have, and I think that”s important. Because it”s not a movie about making people good guys and bad guys. I think ultimately, like Chris said, there is sort of an element of humanism in it that I think is really important. It deals with storytelling, and the power of storytelling.”

“Argo” may still be playing in a theater near you. It lands on DVD/Blu-ray on February 19.