MILK — *** — Sean Penn, James Franco, Josh Brolin; rated R (violence, slurs, profanity, drugs, brief sex, brief nudity, vulgarity, brief gore)

You might think that "Milk" is going to be a pretty one-sided affair.

It is, after all, a biography of slain gay-rights activist Harvey Milk that comes from some pretty outspoken gay filmmakers. And its star is the even more outspoken actor Sean Penn.

Instead, it's a surprisingly balanced drama that boasts a great ensemble cast. The movie is extremely topical as well, especially considering some of the current gay-rights debates.

Penn plays the title character, who went from relative obscurity in New York City to become possibly the most influential public figure in San Francisco's history.

He did so by, first, helping build a gay-friendly business base in the city's Castro District. Having achieved that goal, he then tried to win public office — despite being openly gay, which was even more of a stigma in the 1970s.

But his personal life was considerably more messy and — as shown by his long-term relationship with fellow activist Scott Smith (James Franco), as well as a subsequent one with the less ambitious Jack Lira (Diego Luna).

The film also explores his professional relationship with Dan White (Josh Brolin), a fellow San Francisco city supervisor who wound up gunning down both Milk and Mayor George Moscone (played by Victor Garber) in 1978.

Despite what you may think, director Gus Van Sant and screenwriter Dustin Lance Black (HBO's "Big Love") don't completely demonize White.

They employ the clunky device of voice-over narration, though, as Milk is seen and heard dictating his life story into a tape recorder.

Van Sant employs a more traditional directorial style (a la his hit "Good Will Hunting") and gets terrific performances from his cast. As Milk, Penn is a charismatic and tragic figure. His lead turn here is sure to win him another Academy Award nomination.

Supporting performers Franco, Brolin and Emile Hirsch (who portrays Milk confidante Cleve Jones) are all very good as well.

However, it is a shame that Garber's Moscone is a seeming afterthought as a character.

"Milk" is rated R and features some strong scenes of violence and violent imagery (rioting, a suicide and "hate-crime" beatings), derogatory language and slurs based on sexual preference, scattered sexual language (profanity, slang and other suggestive talk), drug use and references (marijuana), brief simulated gay sex (mostly implied), brief male nudity, and some brief gore. Running time: 128 minutes.

E-mail: jeff@desnews.com