>>> good evening. this day may go down as a pivotal one in the fight to clean up the u.s. military and rid the ranks of the threat of sexual assault . so many of the victims have said the process of reporting unwanted sexual contact must be taken out of the chain of command . but there's been resistance to that and today in front of congress, we got to see the top of the chain on display. the nation's top military commanders all in a row, just one woman among them. it's gotten so bad that today john mccain , a decorated vietnam veter veteran, former prisoner of war , said he could not in good conscience advise women to join the service right now until this gets dealt with. it's where we begin tonight with our pentagon correspondent jim miklaszewski . good evening.

>> good evening, brian. it's not so often you see three and four-star generals called on the carpet all at once, a strong sign that congress is dead serious about tackling sexual assaults in the military. it was a stunning image, all the military's top brass called before the senate to account for the alarming rise in sexual assaults in the military. army chief of staff general ray odierno acknowledged the military had broken the sacred trust with the troops.

>> we have violated that trust because we failed to address these crimes in a compassionate, just, and comprehensive way.

>> reporter: still, the senators were relentless.

>> we need to know how many women and men are being raped and sexually assaulted on an annual basis and we have no idea right now.

>> reporter: senator john mccain said he's disgusted and could not recommend anyone's daughter to join the military.

>> i could not.

>> reporter: the pentagon only estimates as many as 26,000 service members were sexually assaulted or abused last year, but only 3,600 victims actually reported the attacks. senator kirsten gillibrand says when it comes to sexual assault victims are afraid to trust their commanders.

>> they're afraid to report. they fear their careers will be over. they fear retaliation, they feel being blamed.

>> reporter: when a mid shipmen claimed she was raped by three navy football players last year she was disciplined for drinking. her three alleged attackers went unpunished.

>> the message that was being sent loud and clear was that she was getting in trouble for coming forward and yet nothing was happening to the men that were involved in the wrongdoing.

>> reporter: to change that, many lawmakers wanted to take sexual assault cases away from the victim's commanders and hand them to trained special prosecute are yos.

>> not every commander necessarily wants someone in the force and not every single commander can distinguish between a slap on the ass and a rape.

>> having someone in the direct chain of command handling the case just doesn't make sense.

>> reporter: sarah plummer says she was rape as a young marine. her attacker was never prosecuted. despite the injustice she still advises any victims to report the crime.

>> i know it's hard but do it. you have to. you have to say something.

>> reporter: those military leaders said today they're strongly opposed to taking sexual assault cases way from unit commanders, setting the stage for a drawn-out battle with congress and providing little comfort for those victims of sexual assault .

>> jim miklaszewski at the pentagon to start us off, thanks.