leeIt’s been 20 years since Spike Lee made Do The Right Thing, about racial conflict in New York.

AP / Seth Wenig

Twenty years later, the trash can is still crashing through America’s window.

At the climax of Spike Lee’s drama Do The Right Thing, which opened 20 years ago last Tuesday, the eternal battle between love and hate teeters on a razor’s edge. The young black man Radio Raheem has been choked to death by white police after a fight with a Brooklyn pizzeria owner. A seething crowd gathers in front of the shop.

Lee’s character, Mookie, a black pizza deliveryman, stands between the crowd and the shop. He’s shoulder-to-shoulder with Sal, the shop’s Italian owner. They exchange looks of confusion, betrayal and regret.

The crowd stares at Mookie. He’s on the wrong side. Mookie moves over to his brothers, rubs his face, wrestling with the weight of the moment. Then he decides.

“Hate!” screams Mookie as he hurls the metal can through the pizzeria’s plate glass window. The dam bursts. The mob destroys the shop in a frenzy that was both inevitable and completely avoidable.

Much has changed since Do The Right Thing announced Lee’s special gifts to the world. The police choke hold that killed Radio Raheem — a fictionalization of the real death of Michael Stewart in New York City — has long been outlawed. Life on the ravaged Brooklyn block where Lee filmed the movie has improved. Ronald Reagan has given way to Barack Obama.

But for every measure of undeniable progress, Do The Right Thing also points to the divides that remain.

In May, a black New York City undercover cop who was running after a suspect with his gun drawn was shot to death by a white officer. Boarded-up buildings, broken windows and jobless young men still populate that Brooklyn block. And Lee, who wrote, produced and directed the film, insists the racial disconnect at its heart still exists.

“White people still ask me why Mookie threw the can through the window,” Lee said in an interview. “Twenty years later, they’re still asking me that.”

“No black person, ever, in 20 years, no person of color, has ever asked me why.”

That question is what made Do The Right Thing so explosive. Some writers speculated, erroneously, that it would incite riots.

“People were fearful of the backlash,” said Rosie Perez, who played Mookie’s Puerto Rican girlfriend, Tina. “A lot of things happening in the movie were happening in real life. People were afraid when the truth, although a little exaggerated, was put up on the screen for everyone to see.”

Meanwhile, Lee got rave reviews from many influential critics. Roger Ebert cried after watching it at the Cannes Film Festival, where it lost to sex, lies and videotape.

Audiences definitely were not prepared.

Most serious films about race, such as In the Heat of the Night, To Kill A Mockingbird and The Defiant Ones, ended with understanding or even brotherhood. And for every ambitious movie like Watermelon Man or Black Like Me, there were a half-dozen violent, sexy ghetto shoot-’em ups — “blaxploitation” flicks.

Lee had something new to say. “In just three feature films,” critic Gene Siskel wrote then, “Spike Lee has given us more genuine and varied images of black people than in the last 20 years of American movies put together.”

Today, Ebert says Do The Right Thing should have won the Oscar for best picture. “It was so honest about the way people really feel,” he said via e-mail. “No hypocrisy. It generated grief and left us with a central question of American society.”

The best picture of 1989, according to the Academy of Motion Picture Arts and Sciences: Driving Miss Daisy, about the friendship between a white Atlanta woman and her black chauffeur.

It ends on a Thanksgiving in the 1960s, with the chauffeur feeding Miss Daisy a piece of pie.

The riot is sparked by the militant Buggin’ Out, who demands that Sal add some black people to his all-Italian Wall of Fame. Buggin’ notes that Sal’s all-black and Puerto Rican clientele provides his livelihood. Sal responds that if Buggin’ wants to make decorating decisions, he should start his own business.

“They both had good points,” said Lee, with a challenging smile.

Buggin’ tries to organize a boycott, but his black friends have no problem with Sal or his wall. He finally enlists Radio Raheem, whose enormous boom box blasting Public Enemy’s “Fight the Power” has offended both Sal and various black residents.

“It’s absolutely one of Spike’s most interesting and profound films because of that ambiguity,” said Giancarlo Esposito, who played Buggin’ Out. “In our lives, nothing is absolutely black and white, because none of us are the same. So we’re not going to all act the same.”

As night falls on a long, broiling day, Buggin’ Out and Radio Raheem invade Sal’s Famous to press their case, with “Fight The Power” playing at full blast.

Throughout the film, Sal has expressed his love for the neighborhood and its residents, over the racist objections of his son, Pino. Sal has been lenient with Mookie’s meandering deliveries, even saying he’s “like a son to me.” Sal’s shop would have been closed when Buggin’ and Raheem arrived if he hadn’t unlocked it to feed a few neighborhood kids.

But after Raheem doesn’t turn down his radio, and Buggin’ calls Sal a guinea, Sal drops the bomb — the N-word — and destroys the radio with a bat.

Raheem attacks Sal, the police arrive, and Raheem ends up dead.

As his body is carried away in the back of a police car, a black cop runs alongside.

Twenty years ago, amid racial battles stoked by everyone from Lee Atwater to Tawana Brawley, Lee’s film seemed like another salvo. Today, the smoke has cleared, revealing a less contentious world, but one where many of the issues raised by Do the Right Thing still resonate.

Take the Bedford-Stuyvesant block where the movie was filmed. In 1989 there was a crack house and abandoned buildings there; Sal’s pizzeria and the Korean grocery were built on empty lots.

Today, the block is clean, the brownstones well-tended and the residents working class. Yet those lots are still empty, home to cars in various stages of repair. A boarded-up storefront church sits on one corner.

Four young black men stand on the opposite corner at midday, in front of an apartment building with a broken window in the front vestibule. Another man emerges from the building and asks if this reporter’s employer is hiring.

“I’ll tell you one statement I don’t agree with,” Lee says. “ ‘Post-racial society.’ What does that mean? That we’re past it?” He snorts derisively. “We’re not there, we’re definitely not there. Those are people wishing upon a star. It’s not like it’s gonna be presto change-o, abracadabra, Obama Obama — it doesn’t work like that.

“One of the biggest criticisms about Do The Right Thing is, Spike Lee didn’t provide the answer to end racism and prejudice. That’s not my job, I don’t have the answer for that. The film was to show what I felt at the time were issues that needed to be dealt with.”

But still no answers, 20 years later?

“It doesn’t matter,” Lee said. “I’m not gonna sit here and lie and say I have the answer to end racism and prejudice in America.”