Brian J. Tumulty

USA TODAY

WASHINGTON — Democratic Sen. Kirsten Gillibrand of New York is making another bipartisan push to change how the military handles allegations of sexual assault. This time, she has a new ally — the former chief prosecutor of the Air Force.

Retired Col. Don Christensen joined Gillibrand and a bipartisan group of other senators at a news conference Tuesday to request a floor vote on Gillibrand's Military Justice Improvement Act, which would remove commanders from the process of deciding whether to prosecute sexual assault cases and turn that responsibility over to military prosecutors.

Christensen is president of the advocacy group Protect Our Defenders, which provides support services for survivors of sexual assault.

He filed for retirement in September after 23 years in the Air Force — the last four as chief prosecutor — after concluding that the changes needed in how the military handles sexual assaults can't be made from within the service.

Christensen said decisions on whether to prosecute sexual assault cases are too often are made by commanders who are friends of both the victim and the person accused.

"I heard the voices of survivors who are not being taken care of,'' he said. "The reality is, the commanders cannot solve this problem because too often they are the enablers."

Some of the obstacles Christensen encountered in prosecuting sexual assault cases were highlighted in a recent New York Times Magazine story.

"The military's approach to sexual assault seems to be a brick wall that won't crumble,'' Sen. Chuck Grassley, R-Iowa, said at Tuesday's news conference. He was joined by fellow Republican Sens. Susan Collins of Maine, Rand Paul of Kentucky, Ted Cruz of Texas and Dean Heller of Nevada.

Most Senate Democrats support Gillibrand's bill, but some say a series of reforms enacted earlier this year should be given time for implementation.

Gillibrand's bill received 55 votes earlier this year, five short of the 60 needed to overcome a threatened filibuster.

A handful of senators who voted against Gillibrand's bill earlier this year told her they did so in order to give the military time to implement the new reforms, which include the assignment of a personal advocate to each alleged victim of sexual violence.

Gillibrand said she hopes Christensen's advocacy — and the lack of significant improvements over the last several months in the military's response to sexual assault allegations — will persuade some senators to change their positions. Her bill could be offered as an amendment to the fiscal 2015 National Defense Authorization Act during this month's lame-duck session.

The House and Senate Armed Services committees are working on a compromise version of the bill that could come to the House and Senate floors as early as this week.