An Air Force officer’s decision last year to reverse a jury’s guilty verdict in a sexual assault case has prompted Republicans and Democrats to joined forces on ambitious legislation to change the military justice system.

On both sides of the Capitol, lawmakers have interpreted Defense Secretary Chuck Hagel’s recent proposal to essentially strip commanding officers of their ability to reverse convictions of service members as a catalyst to revise the decades-old Uniform Code of Military Justice.

Congress repeatedly has challenged the military’s lack of resolve in fighting sexual assault in its ranks, an offense considered far more prevalent than the reported cases of 3,192 in 2011, the most recent figure available. Former Defense Secretary Leon Panetta said that because so few victims report the crime, the real number is closer to 19,000 assaults.

Hagel acknowledged the problem earlier this month in announcing his proposal to eliminate the discretion of a commanding officer to overturn a court martial ruling, except for minor offenses, and to require a commanding officer to explain in writing any changes that are made.

The crime of sexual assault in the ranks “is damaging this institution. There are thousands of victims in the department, male and female, whose lives and careers have been upended, and that is unacceptable,” the secretary said.

A single case has set off a recent outcry in Congress.

Lt. Col. James Wilkerson, a former inspector general at Aviano Air Base in Italy, was found guilty last year of charges of abusive sexual contact, aggravated sexual assault and three instances of conduct unbecoming of an officer and a gentleman. The incident involved a female contractor.

Wilkerson was sentenced to a year in prison and dismissal from the service, but Lt. Gen. Craig Franklin, commander of the 3rd Air Force at Ramstein Air Base in Germany, reviewed the case and overturned the jury’s verdict of guilty.

Franklin explained in a six-page letter to the Air Force secretary that he found Wilkerson and his wife more believable than the alleged victim.

The ability of a commanding officer to reverse a jury verdict creates a single impression for victims of sexual assault in the military, Sen. Claire McCaskill, D-Mo., told senior officers at a congressional hearing last week. Those women think “no matter what happens at the trial, no matter if they believe me, some general is going to decide I’m a slut,” McCaskill said, capturing the frustration and anger over the case.

In the slow-moving Congress, lawmakers are quickly writing legislation to change the Uniform Code of Military Justice, which was established in 1950 and was revised in 1968 and 1983. Separate measures in the House and Senate are expected to become provisions in annual defense policy bills, one of the few pieces of legislation that Congress passes every year.

The Armed Services committees are expected to complete the bills in June.

Sen. Kirsten Gillibrand, D-N.Y., the new chairwoman of the Senate Armed Services personnel subcommittee, is working with members in both parties on legislation to give Judge Advocate General prosecutors the discretion on whether to go to trial, and to largely strip commanding officers of the ability to toss out a verdict.

“Our goal would be to remove all decision-making out of the chain of command about whether to prosecute a case and whether to bring a case to the chain of command,” Gillibrand said in a recent interview. “And it would not just be for sexual assault. We’re looking at all violent crimes.”