WASHINGTON » Victims of sexual assault and violence in the military told Congress today they’re afflicted with a slow and uncaring system of justice that too often fails to hold perpetrators accountable and is fraught with institutional bias.

They testified to a Senate panel examining the military’s handling of sexual assault cases that the military justice system is broken and urged Congress to make changes in the law that would stem the rape, sexual assault and sexual harassment that they said are pervasive in the service branches.

Defense Department officials said they have taken aggressive steps to combat sexual assault in the ranks. In written testimony to be delivered later today, Robert Taylor, the Pentagon’s acting general counsel, called sexual assault an "abhorrent crime" that does enormous harm to the victim and undermines the good order and discipline that is essential in military units.

Rebekah Havrilla, a former Army sergeant, told the panel that she encountered a "broken" military criminal justice system after she was raped by another service member while serving in Afghanistan. Havrilla described suffering from post-traumatic stress disorder and described how her case was eventually closed after senior commanders decided not to pursue charges.

"What we need is a military with a fair and impartial criminal justice system, one that is run by professional and legal experts, not unit commanders," Havrilla said.

BriGette McCoy, a former Army specialist and a Persian Gulf war veteran, said she was raped when she was 18 and at her first duty station. But she did not report it. Three years later, she reported being sexually harassed and asked for an apology and to be removed from working directly with the offender.

"They did remove me from his team and his formal apology consisted of him driving by me on base and saying ‘sorry’ out of his open car door window," McCoy told the Senate Armed Services personnel subcommittee.

The subcommittee’s hearing comes as members of Congress are expressing outrage over an Air Force general’s decision to reverse a guilty verdict in a sexual assault case that is spurring support for legislation that would prevent commanding officers from overturning rulings made by judges and juries at courts-martial proceedings.

Anu Bhagwati of the Service Women’s Action Network told the panel that commanders are unable to make impartial decisions because they usually have a professional relationship with the accused and, often times, with the victim as well. Bhagwati, a former Marine Corps captain, said court-martial cases should be left in the hands of "trained, professional, disinterested prosecutors."

Under military law, a commander who convenes a court-martial is known as the convening authority and has the sole discretion to reduce or set aside guilty verdicts and sentences or to reverse a jury’s verdict.

Defense Secretary Chuck Hagel has ordered a review of Air Force Lt. Gen. Craig Franklin’s decision to overturn the sexual assault conviction against Lt. Col. James Wilkerson, a former inspector general at Aviano Air Base in Italy.

Sen. Kirsten Gillibrand, the chairwoman of the military personnel subcommittee, called the Wilkerson case "shocking" and promised to take a hard look at the military justice system. Nearly 2,500 sexual violence cases in the military services were reported in 2011, but only 240 made it to trial, Gillibrand said.

Wilkerson, a former inspector general at Aviano Air Base in Italy, was found guilty on Nov. 2 by a jury of military officers on charges of abusive sexual contact, aggravated sexual assault and three instances of conduct unbecoming of an officer and a gentleman. The victim was a civilian employee. Wilkerson was sentenced to a year in prison and dismissal from the service.

Wilkerson was at the U.S. Naval Consolidated Brig in Charleston, S.C., until Feb. 26, when Franklin exercised his discretion as the convening authority. Franklin reviewed the case over a three-week period and concluded "that the entire body of evidence was insufficient to meet the burden of proof beyond a reasonable doubt," Hagel wrote in a March 7 letter to Sen. Barbara Boxer, D-Calif.

But Hagel told Boxer neither he nor the Air Force secretary is empowered to overrule Franklin, who is the commander of the 3rd Air Force at Ramstein Air Base in Germany.

Boxer said during testimony before the subcommittee that "immediate steps must be taken to prevent senior commanders from having the ability to unilaterally overturn a decision or sentence by a military court."

Taylor, the acting general counsel, said in his written testimony the Defense Department is examining the role the convening authority plays, including a commander’s power to set aside a court-martial’s findings. But Taylor also stressed that commanders have long held this authority and it is directly tied to the need for the "portability" of military justice throughout the world and the need for senior officers to maintain discipline in the ranks.

In the wake of Franklin’s decision, Reps. Jackie Speier, D-Calif., Bruce Braley, D-Iowa, and Patrick Meehan, R-Pa., introduced legislation Tuesday in the House of Representatives that would strip military commanders of the power to overturn legal decisions or lessen sentences. Their bill would amend the Uniform Code of Military Justice to take away the power of a convening authority to dismiss, commute, lessen, or order a rehearing after a panel or judge has found the accused guilty and rendered a punishment.

Sen. Claire McCaskill, D-Mo., a member of the personnel subcommittee, plans to introduce legislation soon that would change the Uniform Code of Military Justice by preventing a convening authority from overturning a decision reached by a jury. The legislation also would require the convening authority to issue a written justification for any action.

"This is not a crime that we’re going to train our way out of," said McCaskill, who emphasized the need for the strong and effective prosecution of offenders.

Brian Lewis, a former Navy petty officer, told the subcommittee not to forget that many victims of sexual assault and harassment in the military are male. Lewis said he was raped in 2000 by a non-commissioned officer who outranked him. His commanders ordered him not to report the crime to Naval Criminal Investigative Service. Lewis said he was later misdiagnosed with having a personality disorder and he was discharged from the service in 2001.

"I carry my discharge as an official and permanent symbol of shame, on top of the trauma of the physical attack, the retaliation and its aftermath," Lewis said.

Sen. Angus King, I-Maine, asked whether the culture would change if the laws were overhauled. Lewis described the limitations of military law, arguing that it was unconscionable that punishment is solely at the discretion of a single individual and the offense of sexual assault is merely a year in prison.

"The military does not value what happened to the victim," Lewis said.