(RNS1-JUNE14) Director Reed Cowan and producer Chris Volz of “8: The Mormon Proposition” outside the Salt Lake City, Utah, headquarters of the Church of Jesus Christ of Latter-day Saints. The documentary explores the role of Mormons in repealing gay marriage in California. For use with RNS-PROP8-FILM, transmitted June 14, 2010. Religion News Service photo by David Daniels.

(RNS) Is it a love letter from liberal Mormons to their church, or a Michael Moore-style hit piece on Mormon leaders?

The film “8: The Mormon Proposition,” explores the role of the Church of Jesus Christ of Latter-day Saints in repealing same-sex marriage in California nearly two years ago. After debuting at last winter’s Sundance Film Festival, the film opens in 15 cities nationwide on Friday (June 18).

Director Reed Cowan had originally set out to document homeless and suicidal Mormon teens when another topic caught his attention.

In 2008, about six months after California’s Supreme Court had struck down a ban on gay marriage, voters approved Proposition 8, a referendum that restricts marriage to heterosexual couples.

The LDS church’s support for the referendum went all but unnoticed — for a time — until Mormons’ significant deployment of moral and financial capital was discovered. Earlier this month, the LDS church agreed to pay a $5,500 fine for not reporting all of its non-monetary contributions in support of Prop 8.

In the documentary, gay Mormon couples, families and ex-church members chronicle the church’s campaign behind Proposition 8.

Televised advertisements endorsed by the church urged the public to preserve traditional families. Church leaders warned that same-sex marriages ruin society and endanger souls, and mobilized their congregations accordingly.

“Money, volunteers and a message. One organization with all three of these rose above the rest that summer, saying to the rest, `Come follow me’,” says Dustin Lance Black, a narrator of the film. Black, best known for penning thescreenplay for the Oscar-winning film “Milk” also writes for HBO’s “Big Love,” which explores polygamy among modern fundamentalist Mormons not affiliated with the LDS church.

Black is not the only cast or crewmember with Mormon roots. Director Reed Cowan, co-director Steven Greenstreet and producer Emily Pearson also grew up in the faith.

“I feel like this film in a lot of ways was my second mission,” Greenstreet said. “I served a mission for the church — went out and pounded pavement and knocked on doors — so this is my second.”

Mormon youth were taught how to persuade their friends and families to vote on Proposition 8, according to “8.” Elder Quentin L. Cook, a Mormon leader, called on devotees to donate their “means and time” to the cause.

“When Mormons heard `means and time’ in their prophet’s call, it was like code,” says Pearson in the film. “They got the message.”

Critics of the film, including the Mormon church, said “8” takes a biased stance against the church.

“Clearly, anyone looking for balance and thoughtful discussion of a serious topic will need to look elsewhere,” said Kim Farah, a LDS church spokesperson.

After the film debuted at Sundance, LDS church spokesman Scott Trotter told the Salt Lake Tribune that, “Judging from the trailer and background material online, it appears that accuracy and truth are rare commodities in this film.”

David Melson, head of the gay and lesbian Mormon organization Affirmation, said the film was not so much anti-Mormon as a “love letter” to the church.

“As a gay Latter-day Saint, I had to kind of emotionally separate my belief in the doctrines of the church with my belief in their political structure,” he said.

Melson converted to the faith years after he came out as gay. He said he was clear about his sexuality from the start — out to his bishop and church leaders.

Melson and Greenstreet said the LDS church strays from the doctrine of “free agency,” the idea that believers can make their own moral decisions on tough issues.

“Is this the same church I grew up with?” Greenstreet said. “It boggles my mind and disappointed me that the first church I grew up with was behind this.”

For director Cowan, the most important audience of the film are potential voters.

“This is not a gay film. This film is an examination of faith, obedience and incursions in to politics by religion.”