Some years back a young Kenneth Lonergan visited Italy, his first trip to a country where English wasn’t the predominant language. He experienced a powerful bit of self-awareness. “My God,” he thought. “These people have been here the whole time I’ve been alive.”

It’s one of those moments that is more striking than it sounds, particularly for a writer curious about the world and how people respond to it, are affected by it and, most importantly, are ignorant to it. Having always been interested in other people’s points of view, the size of the world and the limitations of his own experiences with it, it was a seminal moment for the writer/director, one that tucked itself away in the recesses of his mind until it was called upon to flavor his latest effort, “Margaret.”

The film, which has seen an embattled legal and post-production history, tells the story of a young woman’s own watershed moment of epiphany, when suddenly the world seemed to expand beyond the borders of her privileged Manhattan life.

“This is someone who grows up in the Upper West Side, which is a very centrally located, parochial neighborhood,” Lonergan says, calling from New York, of the film’s main character, Lisa Cohen (Anna Paquin). “You don’t know, when you grow up on the Upper West Side, that you’re not in the center of the world. You grow up in Kansas and you know there’s a big world out there. When you grow up where I grew up, you think, ‘That’s it.’ And so you step out and you realize there’s a lot more going on. So it was really important to me that she’s never been to a bus driver’s house before, she’s never been in a police station, she’s never been in a lawyer’s office, she’s never seen anyone die.”

For a long time the film was just labeled “Bus Film” in Lonergan’s computer, so called for the story’s inciting incident. The narrative flow seems simple enough: Lisa has a hand in a tragic bus accident that takes a pedestrian’s life. The blame is shared with the bus driver (Mark Ruffalo), who was distracted by Lisa and ran a red light. Burdened by guilt and a naive yet touching desire for justice, Lisa becomes close with one of the victim’s friends, explores legal options to have the bus driver fired at the very least, approaches him in order to purge their guilt with a not-so-simple admission and basically bends over backwards to understand why something so horrible and random had to happen in the first place.

The themes Lonergan wanted to explore stemmed from a Gerard Manley Hopkins poem, “Spring and Fall,” that tells of a young girl — Margaret — mourning the change of seasons. But ultimately the lyrics are about the shift from adolescence to adulthood, the reality check that comes when suddenly the world isn’t so mysterious, at least not for the romantic and exciting reasons it is when seen through the eyes of youth.

“Little kids grow up discovering the world that’s shown to them,” Lonergan says, “and then when you become a teenager, it kind of shrinks a little bit. I think when you get past that point, one of the important things is that you see there is more to the world than yourself. Elaine May had seen an early cut of the film and she said to me, ‘Only a teenager could think that she could have that much affect on the world,’ which I thought was very interesting and apt and kind of touching and sad.” May’s daughter, Jeannie Berlin, plays the victim’s friend, Emily, in the film and has received some recognition this awards season.

Lonergan was also interested in keeping the full breadth of Lisa’s experience in the eye of the camera. It was important to him that the character’s life continued in all of its elements, rather than follow along the central narrative thread. And so the film therefore resembles a bit of a willfully messy construction, characters played by major actors (Matt Damon and Matthew Broderick) coming and going in brief exchanges, while other key moments in a young adolescent girl’s life (such as losing her virginity) play out in poignant, mundane strokes.

“In many movies,” Lonergan says, “someone’s involved in the pursuit of a criminal or a story or a trial, you see them in their life and then you see the story start. And then all you ever see is them getting out of work and going to meet with the policemen or whatever it is. I always wondered, ‘What do they do all day long while this is going on?’ So I was very interested in keeping her entire life alive as the story goes on. She may be pursuing this agenda and she may be trying to work out all the difficulty she’s going through, but she still has to go to class and she still has to deal with her mother and she still has to deal with everything we have to deal with all day long. I’d never seen that done before. It may have been done and I just didn’t see it but I thought that was an interesting thing to do and that suggested a movie right away.”

Indeed, Lonergan always saw “Margaret,” which has been noted as a “novelistic” piece of filmmaking, as cinematic material. Even when he allowed himself a 375-page first draft, he wanted it on the screen. He toyed for a time with the idea of a mini-series, but eventually he honed it down to the essence he wanted, never really envisioning it for literature or the stage (where he has established himself quite authoritatively as a Pulitzer Prize-nominated playwright).

“The rest of the city going about its business in these different neighborhoods is really, really important to the story and is something I was interested in incorporating,” he says. “So that suggested a film rather than a play. Outdoor atmosphere is not something the theater does very well.”

“Margaret,” which was filmed in 2005, was Lonergan’s sophomore effort following 2000’s “You Can Count on Me.” He says his learning curve on his debut was “perpendicular” and that he was very much learning on the job, developing visual ideas during discussions with his cinematographer, etc. This time around, though, he developed those ideas early on, including that notion of a vast metropolis going on about its business as a central character fights against the grain to see justice served.

“I wanted her to be just one person in the whole city,” he says, “no matter what was going on with her. Where I’m standing now, there must be 50,000 people within a five-minute walk, and I was interested in the idea of, with a camera, trying to convey that whatever you’re doing, you’re surrounded by people doing things that are either much more important or much less important.

“Like, we’re having this conversation, and I’m sure someone nearby is dying of something and I’m sure someone nearby is having a very good time doing something else. That goes on all day long, all over the world, and I just thought that was something that would be very interesting to convey visually. Also, that’s what she’s up against. It’s not the details of the lawsuit or the fact that the bus driver is one kind of a person or another, but just that the world is so big. And this is a very good city for demonstrating that visually.”

He also says he wanted the exteriors to be geographically accurate. “I didn’t want to have someone step out of a building on 72nd Street and walk into a restaurant in Greenwich Village,” he says. “I wanted to be as truthful to the neighborhoods and the locations as possible, and for the most part we were successful in being able to do that.”

Lonergan had cast actress Anna Paquin in the London production of his play “This is Our Youth” and was about a third of the way through writing “Margaret” when he decided she was perfect for the role of Lisa. What really struck him as being unique about her, he says, was a balance of sensitivity with energy and vitality.

“My wife, J. Smith-Cameron [who plays Lisa’s mother in the film], refers to some actors as ‘front foot actors’ and some actors as ‘back foot actors,'” he says, “meaning they’re sort of moving forward or they’re waiting and reacting. And Anna is so driven. There are many sensitive and delicate performers out there, but she had the sensitivity and the burning drive, which the character had to have. Lisa is really trying very, very hard to do this very difficult thing and she gets quite far with it. So I think there is something to be said for her, despite the fact that she has trouble seeing past her own horizon.”

That idea of not seeing past one’s own horizon begins to take on an even deeper meaning when considering “Margaret” as a film about a city coming to grips with itself in the wake of its own tragedy. It’s not that Lonergan felt any strong desire as a New Yorker to offer up thematic commentary about 9/11 when he set out to write the film (which is full of student arguments and debate sessions relating to the event, still very fresh all those years ago). But they started to work themselves in nevertheless.

“I wrote it around 2001 to 2002,” he says, “and I remember at the time, almost within days after the attacks, everyone was asking, ‘How has this changed your view of America and your view of New York and how has this changed your view of life?’ And my thought at the time was, ‘My God, I don’t know. It’s so immense. How are you supposed to know what you think of anything this size, that fast?’ Whatever I was thinking and feeling about it came out in what I was writing at the time, which was ‘Margaret.'”

Around Paquin, Lonergan built a cast of talented performers. He wrote the part of the mother for Smith-Cameron and had Paquin in mind for the lead, but with a wealth of stellar actors committing, he wasn’t sure where they’d go immediately. He didn’t know if Mark Ruffalo would play the bus driver or one of the teachers, for instance, but things eventually started clicking into place.

“What’s funny is you’re looking for what you imagined, and sometimes you get it,” he says. “And then when you don’t, you branch out your idea of what the character should be.”

In particular he notes Jean Reno’s brief portrayal of a gentleman seeing Lisa’s mother, who eventually walks the delicate thematic line of political correctness that Lonergan threads throughout.

“That was a very difficult part to cast, because it’s such an elusive character,” he says. “But I think he’s just wonderful. He has a very elusive quality but a very menschy quality.”

Getting back to the film’s inciting incident, that harrowing bus accident, Lonergan says if that scene didn’t work, there would be no movie; it happens in the film’s first 10 minutes and in every scene that follows, there’s not one moment when Lisa is not affected, when what she does isn’t driven in some way by what happened to her. But while it was originally just a scene between Paquin and Allison Janney (who is pitch-perfect in virtually 2% of the film as the dying victim), something Berlin happened to witness added further thematic heft.

“Jeannie had told me while we were shooting that she had seen a terrible accident on Broadway, just by coincidence,” Lonergan says. “What was really bizarre about it was that a crowd gathered, just a wall of people stood around and watched this truck driver, whose truck had blown up in the middle of Broadway and he was very badly burned. She said all these bicycle messengers just pulled up and these people just stood there like an audience watching this guy die, basically.”

It led Lonergan to include a circle of extras around Paquin as she acted out the scene with Janney. “Every time they finished a take,” he says, “everybody was just sort of in shock, because Anna and Allison were so real. And this is all day long. You hold up the traffic. You have people honking. Everybody’s mad at you. The crew is working really, really hard to keep the street clear. It’s very difficult shooting in the middle of the city in the middle of the day.”

When coming around to the issue of “Team ‘Margaret,'” a grassroots campaign started by critic and journalist advocates of the film demanding more exposure, Lonergan understandably finds it all incredibly heartening. Along with being considered one of the year’s best films by a host of critics, the Chicago Sun-Times’ Roger Ebert and CNN’s Tom Charity among them (in addition to being an obvious favorite around these parts and picking up major nominations from the Chicago Film Critics Association and the London Film Critics Circle), “Margaret” has a lot of supporters in its corner. Lonergan noted his appreciation in a previously released statement as the movement built to a fever pitch.

“I couldn’t be more touched by the outpouring of support from critics and twitterers, as well as the petition campaign on behalf of ‘Margaret’ for the released cut,” it reads. “I support this cut wholeheartedly and want people to see and like it, and the actors deserve to be seen and appreciated for their amazing work. It would mean everything to me if the film could at least have a fair chance at a life of its own.

“Filmmaking, like any other art, is a very profound means of human communication; beyond the professional pleasure of succeeding or the pain of failing, you do want your film to be seen, to communicate itself to other people. They don’t have to like it, but connecting your inner life, your view of life, to the inner life and views of others is really and truly what it’s all about, and I desperately want ‘Margaret’ to have that chance to reach people, regardless of its ultimate merits.”

With New York’s Cinema Village in the midst of an on-going booking for the film and Los Angeles’s Cinefamily planning a similar engagement starting on January 27, at least “Margaret” is beginning to reach a wider audience than it did during it’s limited official release in September (which netted it a paltry $46,000 in box office receipts). Time will tell if a home video release will help bring it to an even broader spectrum of viewers, but Lonergan is regardless humbled by the rally cry of its supporters.

“It’s a miracle,” he says. “I don’t even know what to say about it. I still can’t quite take it in. You want to communicate with people when you write something, and the fact that people care about the work the actors and I did to champion it this way, I don’t know what else to say about it except that it’s a miracle. I don’t actually believe in miracles, per se, but I believe in this one.”

For year-round entertainment news and awards season commentary follow @kristapley on Twitter.

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