DURING A Senate hearing on sexual abuse in the military, the country’s top uniformed leaders were asked whether any commanders had been relieved of duty for tolerating an environment that allowed inappropriate sexual conduct. The chiefs of the Army, Navy, Air Force and Marine Corps were unable to cite a single case, though they said such a failure might be included in assessments of more generalized command breakdowns. It was an unsatisfying response that tended to undermine the leaders’ assurances that dealing with an epidemic of sex crimes is best left to the traditional chain of command.

The service chiefs and other brass appeared Tuesday before the Senate Armed Services Committee to acknowledge the severity of the problem and their failure to confront it despite decades of promises. “I took my eye off the ball in the commands I had,” said Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, citing the demands of being at war for more than a decade. But he and others cautioned members of Congress — many of whom are fed up with the Pentagon’s inability to deal with an issue that emerged with the 1991 Tailhook scandal — not to overreach as it considers legislative changes to military policy.

In particular, they are opposed to taking sexual-assault cases out of the hands of commanders by giving military prosecutors the authority to decide which cases to try.

The military is a unique institution. Concerns about a commander’s ability to maintain discipline and unit cohesion must be taken into consideration and carefully studied. But after 20 years of unmet promises on this issue, deference to that concern can no longer be assumed. Nor did the officers help their case when they acknowledged a lack of effort in finding out how other countries have dealt with this issue. “Thank you for that tip,” the chief of naval operations said after a senator wondered whether anybody had looked at the experiences of allies such as Britain, Canada and Israel, which have removed prosecution of serious crimes from the chain of command.

The questioning by senators, sometimes withering, revealed problems in how the military collects data and views the seriousness of different crimes. A recent Defense Department report estimated that there were 26,000 incidents of unwanted sexual contact and sexual assault in 2012 but that only a sliver, 3,374, were reported. Advocates say that is because victims think they will be ignored, blamed or retaliated against by officers who either lack training in how to investigate these crimes or don’t want to acknowledge problems in their units that could reflect badly on their command.

“I’m a little taken aback. It sounds like you all are very bullish on the status quo,” Sen. Claire McCaskill (D-Mo.) told a panel of officers who do criminal investigations, and “the status quo is not acceptable.” Congress is right to no longer accept the military’s promises that it will solve the problem on its own.