WATCH LIVE: Joint Chiefs testify on sexual assaults in military

In testimony, Joint Chiefs Chairman Gen. Martin Dempsey and the service chiefs opposed stripping commanders of the power to decide where sexual assault cases are prosecuted, defending the current system.

“I urge that military commanders remain central to the legal process,” Dempsey said in written testimony.

“The commander’s ability to preserve good order and discipline remains essential to accomplishing any change within our profession," he said. "Reducing command responsibility could adversely affect the ability of the commander to enforce professional standards and, ultimately, to accomplish the mission.”

For the first time in history, all six members of the Joint Chiefs of Staff will testify at the hearing.

Sen. Claire McCaskill (D-Mo.), a former prosecutor, who sits on the committee, blasted the military on CBS "This Morning" for being "20 years behind" when it comes to the prosecution of sexual assault cases.

A rash of incidents has shined the spotlight on the problem of sexual assaults in the military. A recent Pentagon report estimated 26,000 assaults occurred last year, an increase of more than a third.

Read more on The Hill's DEFCON blog.

—Jeremy Herb contributed.