So tell me, whats your nigga? Cleve Jones, a veteran gay activist working as historical consultant on Milk, recalls Sean Penn asking as the actor prepped for his role as the late San Francisco city supervisor Harvey Milk. A little horrified by Penns question, Jones answered, What? Penn repeated the question: Whats your nigga? I said, Sean I have no idea what youre asking me. He said, Come on, young black men on the street ask Hey, nigga whats going on? What is the equivalent word in your community? And I thought for just a moment and said, Well, that would be girl. In a bleating falsetto, Jones demonstrated: GI-I-IRL!!! Often called the greatest actor of his generation, Penn may also be the butchest. No movie star since Marlon Brando (or, some would argue, Mel Gibson) has possessed so pure a combination of the qualities -- rogue politics, wild personal life, brooding face, and meat-slab body -- that add up to the American ideal of masculinity: unaffected, principled, but impulsive strength. He is not, in other words, the first actor you might cast as Milk, who fearlessly put the camp in campaign (My fellow degenerates, began a patriotic speech) and was one of the first openly gay men elected to public office in this country. But after Brokeback Mountain, after Capote, is it still significant when a top-tier straight male movie star decides to play gay? In Penns case, it is -- not only because of his personal symbolism, but also because the films premiere this month coincides with a presidential election that, in some ways, parallels Milks landmark race. Milk was the Barack Obama of his time and place. When he ran for the board of supervisors, Milk made grand promises to heal deep social tensions in his city. At his swearing-in, he said, A true function of politics is not just to pass laws, but to give hope. Dianne Feinstein, then president of the board, responded, Hope is fine, but you cant live on hope. Harvey Milk was not butch. He was not exactly effeminate, either, but his manner was overtly gay. Vintage footage in the documentary The Times of Harvey Milk shows that Milk carried himself, as many gay men do (much as we hate to think about this) in a distinct style. Most of us are lit from deep inside by a subtle, unmistakable edge of self-consciousness that is the closets bequest. Gaydar is the ability to recognize this quality: the faint but indelible separation between mind and body that develops when a man has spent years wondering if everyone can see the truth about him. Penns performance in Milk nails these mannerisms and inflections and, movingly, depicts their evolution. At the beginning of the film, Milk is audacious, but he quivers like a lapdog while seducing Scott Smith (played by James Franco), who became his lover. As time goes on and Milk becomes a man in full, he does not cast off the quiver but fills it with power. A homosexual with power, he brags -- and marvels -- in a confrontation with San Francisco mayor George Moscone just before the two are assassinated. Thats scary. This incremental change in the way Milk inhabits his own body is cued by the screenplays fine structure, in which the characters sentimental and political educations are inextricable. In a conversation with Milks filmmakers about how Penn crafted this performance (Penn declined to be interviewed), screenwriter Dustin Lance Black said the script shows love and politics to be absolutely related, because it was illegal to be in love and do the things that showed you were in love with a gay man. Director Gus Van Sant added, Almost all of Seans depiction of Harvey is oriented toward Harveys political drive. There is some sexual drive too. I think that was sort of entertaining to Sean. Dan Jinks, one of the movies producers, reminded Van Sant, You said that the first time you sat down seriously to talk to Sean about it, he had strong feelings about a heterosexual guy playing this role. The director explained, Another thing Sean really liked about it was that it was playing with his strongly heterosexual image. Playing a strong gay character was going someplace he hadnt gone before. He plays Harvey as a gay man with a lot of sexuality whos very affectionate, very physical, said Bruce Cohen, another executive producer. While filming a campaign victory celebration scene, for example, Sean Penn got off his motorcycle, and he was very excited, and he started kissing people, kissing these extras on the way in, Jinks recalled. Afterward, there were all these male extras that said, Oh, my God, Sean Penn just kissed me! (Van Sant said that another scene, in which Penn and Franco share a long, deep, hungry kiss, was inspired by a Douglas Gordon video installation called The Kiss, which he sent Penn and Franco to watch together.) Milk depicts a lot more than kissing, though. The sex scenes are every bit as erotic and explicit as such scenes in To Die For or Van Sants other films. And though Van Sant seemed completely comfortable talking about these scenes, Jinks said, If people walk out of our movie talking about sex scenes, we would have failed in our goals for the movie. By the same token, Cohen offered, if people walk out talking about the lack of sex scenes, la Philadelphia, we would also fail. Milk, he pointed out, marks a major turning point in Hollywoods depiction of the place of sex in gay characters lives: Its the first studio film where the sex scenes with gay men are in the same places and exactly the same amount as they would be with straight characters. Read James Franco's interview with Milk screenwriter Dustin Lance Black here. Send a letter to the editor about this article.