Kori Cioca, US Coast Guard, and husband Rob in an emotional interview, from “The Invisible War.” (Cinedigm/Docurama Films)

Documentary filmmaker Kirby Dick’s “The Invisible War” is a study of rape in the U.S. military that leaves viewers weeping and seething. It may be the Los Angeles director’s most harrowing film to date, but it’s not a departure from his usual concerns.

Dick’s first critical success was 1997’s “Sick: The Life and Death of Bob Flanagan, Supermasochist,” an account of a performance artist who used erotic pain to contend with his cystic fibrosis. Subsequently, the director made documentaries about the sexual politics of the Motion Picture Association of America’s R and NC-17 labels (“This Film Is Not Yet Rated”), child molestation by Catholic priests (“Twist of Faith”) and closeted gay politicians who support anti-gay laws (“Outrage”). Even “Derrida,” the 2002 biography of the French philosopher that was Dick’s first collaboration with “Invisible War” producer Amy Ziering, touched on gender roles.

“I am drawn to these sorts of subjects,” Dick says. “They’re fertile ground for discussing larger issues in American society.”

“The Invisible War” reports, using Defense Department statistics, that more than 20 percent of women in the military have reported a sexual assault. The department estimates that about 80 percent of such assaults, which affect many men as well as women, are not reported. (Some of these same numbers have been featured recently in a “Doonesbury” story line.)

The film notes that women are often penalized for alleging sexual assault and are required to report such attacks to their chain-of-command superior, who in some cases is the accused rapist. Single women raped by married men have been charged with adultery, while their attackers go unpunished.

Director Kirby Dick poses for a portrait during the 2012 Sundance Film Festival at the Getty Images Portrait Studio at T-Mobile Village at the Lift on January 21, 2012 in Park City, Utah. (Larry Busacca/Getty Images)

The standard U.S. military approach to sexual assault is designed “to help women get raped better,” Army criminal investigator Sgt. Myla Haider says in the movie.

“We aren’t going to comment on the film or the cases in the film,” says Cynthia O. Smith, a spokeswoman for the Defense Department’s press office. But she notes that procedures have changed since Leon E. Panetta became defense secretary last year.

After interviewing more than 70 victims — they use the term “survivors” — Dick and Ziering are not disinterested observers. They visited Washington early this month with the hope of reaching filmgoers and policy shapers.

“There are two audiences for this movie,” says Dick, sitting with his collaborator in a downtown theater one morning. “There’s the usual documentary audience, and then there are the decision makers.”

Since “The Invisible War” won the Audience Award for best documentary at the Sundance Film Festival in January, copies have circulated at the Pentagon and on Capitol Hill. “We call it a grass-top, rather than a grass-roots, approach,” Ziering says.

“We know that Panetta has seen it, and that he was very moved,” Dick says. The movie now ends with the note that Panetta has changed procedures for prosecuting sexual assault in the military, taking responsibility for the cases away from local unit commanders.

Smith says she can’t confirm that Panetta has watched the movie. But at a news conference in April, the defense secretary announced several new policies, including the one mentioned in the documentary. He also described the creation of a special victims unit and a requirement that “DoD sexual assault policy be explained and briefed to [new recruits] within 14 days of entering active duty.”

These changes come too late to benefit the women (and one man) in the film, who were chosen from more than 120 people contacted through social media, therapists, victims’ advocates and word of mouth.

“I did all the survivor interviews,” Ziering says. “That was important because they were mostly women. There was just a different level of comfort to have a woman interview them.”

Initially, she says, “they all thought they were the only one. They had kept it all inside. Nearly all of them had attempted suicide.”

The interviews were often painful, Dick adds, but for some people, they were therapeutic. “Several husbands said to us, ‘You saved our marriage. Before this movie, I didn’t really understand what she went through.’ ”

All the interviewees, the filmmakers stress, were reluctant to participate in a movie that might damage their former service’s reputation.

“Nobody wanted to be involved in an anti-military project,” Ziering says. “These were all people who were proud to have served in the military. Many of them had hoped to spend their entire careers in the military.”

For Ziering, one disturbing aspect of the assaults is that few of the victims have found it possible to move on. “A lot of the survivors aren’t working,” she says. “Some of them had very successful military careers, but now they’re unemployed. That’s a tremendous loss of human capital.”

The movie’s central thread is the story of Kori Cioca, who was raped and beaten by a supervisor while in the Coast Guard. Viewers see the Veterans Administration repeatedly refuse to pay for reconstructive surgery for her dislocated jaw.

That small part of Cioca’s ordeal has a happy ending, Ziering says. After the movie’s Sundance screening, “A man came up to us in the lobby and said, ‘Tell that young lady that her face will be taken care of.’ He and his wife promised to cover her medical bills. Then another couple heard them and said they’d like to help, too.”

That’s just one case, however, among thousands or more. While making “The Invisible War,” Dick says, he became convinced that “sexual assault in the military is the most underreported significant crime in the country.”

Jenkins is a freelance writer.

The Invisible War

(not rated, 97 minutes) opens Friday at Landmark E Street Cinema.