By Julia Edwards, Globe Correspondent

An Oscar-nominated documentary on the subject of sexual assaults in the U.S. military has catapulted the issue to higher prominence, while providing greater visibility for the Massachusetts congresswoman who has a role in the film, Representative Niki Tsongas.

Tsongas will host a panel discussion and a viewing of “The Invisible War,” on Wednesday at 7 p.m. at Tufts University. The Lowell Democrat makes a short appearance in the film during a scene where she moderates a discussion among female survivors of sexual assault in the military from her Washington, D.C. office.

Tsongas labored for several years in Congress to shed light on the long-hidden issue. Legislation she co-sponsored finally became law last year, allowing victims of sexual assault to request a base transfer, legal counsel and a confidential advocate.

She said in an interview that she first became aware of the problem as a newly elected member in 2007, when she met a female soldier who told Tsongas she carried a knife in her belt when walking around base to protect herself from unwanted advances.

“She told me, ‘I am more afraid of my own soldiers than I am of the enemy,” said Tsongas.

Tsongas teamed up with Representative Michael Turner, a Ohio Republican, to push the legislation. In the Senate, they gained the assistance of then-Senator John F. Kerry.

“Our goal is to create a system where survivors are far more comfortable speaking out and where those who are truly guilty are found guilty,” said Tsongas.

Former Defense Secretary Leon Panetta also took a stance for victims and removed the authority to handle sexual assault cases out of the hands of junior military commanders—who are often in charge of both victim and alleged perpetrator.

``The Invisible War’’ documents the lives of men and women who say they were assaulted and often denied adequate justice from military courts. A 2011 report from the Department of Defense reported 2,723 victims of sexual assault, and advocates say the number would likely be higher if victims were not often intimidated out of speaking.

The film’s director, Kirby Dick, said the actions taken by Congress and the Pentagon are a step in the right direction, but do not go far enough. Based on the interviews he conducted with victims, Dick believes the authority to prosecute such cases must fall to a person completely outside of the chain of command of both victim and perpetrator.

“Most victims feel they won’t get justice because there will be a conflict of interest,” said Dick. ``Until Congress mandates that the military makes this fix, the military is going to continue to have a very serious sexual assault problem.”

Dick nonetheless applauded Tsongas for making the issue bipartisan by working with Republicans like Turner and House Armed Services Committee Chair Buck McKeon.

“Two years ago, when we were making this film, there weren’t a lot of people speaking out about this in Congress. Tsongas was one of the few.” Dick said. “We were grateful that she was standing so strong. Her collaboration with Turner is a real remarkable model of cooperation in Congress.”

Dick said newly confirmed Defense Secretary Chuck Hagel has seen the film. So have 250,000 soldiers who have viewed the film as part of a training program mandated by Tsongas’s bill, he said.

Tsongas has continued speaking out on the subject. She and Turner co-chair the Military Sexual Assault Prevention Caucus, which recently sent a letter to Air Force Secretary Michael Donley, calling the Air Force’s decision to overturn the verdict against Lt. Col. James Wilkerson a “step backward in the service’s commitment to ending sexual assault.”

The case has received national attention. Air Force officials are expected to give a briefing to the caucus about the decision in April, according to Tsongas spokesman Michael Hartigan.