LOS ANGELES  When the movie “Milk” comes next month to Claremont, a college town about 30 miles from here, Patrick Milliner intends to greet it with a candlelight vigil protesting the newly passed state prohibition of gay marriage.

Before this month’s election, Mr. Milliner organized unsuccessful opposition to California’s same-sex marriage ban, Proposition 8. Now he expects the movie, about Harvey Milk, the murdered gay-rights crusader and San Francisco supervisor, to ignite his “Shame on 8” campaign.

“It fits perfectly with the plan,” Mr. Milliner said.

That may be good for the movement. Whether it is also good for the movie is less clear.

The convergence of “Milk,” which portrays gay-rights battles of 30 years ago, and a looming new culture war over homosexual marriage and other issues, has raised unusual expectations around Focus Features’ plan to release the film. It will be shown in a widening group of theaters, beginning with some in New York, Los Angeles and about a dozen other cities on Wednesday.