Sgt. Richard Wrigley / U.S. Army Fort Hood soldiers.

Sexual assaults in the military, long simmering on the Pentagon’s back burner, moved to a roiling boil 10 days ago – and threatened to explode with the announcement Tuesday night of yet another probe into sexual assault by a uniformed member of the U.S. military charged with preventing that very crime.

It was less than two weeks ago that local police near the Pentagon arrested Lieut. Colonel Jeffrey Krusinski, the Air Force’s sexual-assault prevention chief, for drunkenly groping a woman in a parking lot. Now, with the Army investigating an unnamed sergeant charged with preventing sexual abuse at Fort Hood, the pot is rattling atop the stove and threatening to blow up.

There is growing concern inside the Pentagon that the two latest cases make clear the fact that the military cannot be counted on to defend those in its ranks against sexual predators. Followed to its logical conclusion, that means some elements of combating sexual assault may have to be pulled out of the military’s treasured chain of command.

That’s what a growing number of lawmakers want. Senator Carl Levin, the Michigan Democrat who heads the armed services committee, said his panel will begin studying such changes next month. “Tragically, the depth of the sexual-assault problem in our military was already overwhelmingly clear,” he said late Tuesday, “before this latest highly disturbing report.”

Some lawmakers contend the military justice system is too rife with built-in conflicts of interest to ensure that justice is meted out fairly to victims. They point to last week’s Pentagon survey showing an estimated 26,000 cases of unwanted sexual contact last year, a 35% jump over 2010’s estimate.

The military has pushed back, contending that commanders need the ability to punish transgressors – and for that to be witnessed by their comrades – to maintain the military’s cherished “good order and discipline” within its ranks. “It is my strong belief…the ultimate authority has to remain within the command structure,” Defense Secretary Chuck Hagel said last week.

Unfortunately, the recent spate of sexual assaults, beginning in 2011 with more than 30 trainers at Lackland Air Force Base in Texas who allegedly abused more than 60 recruits, suggests good order and discipline is in short supply.

In the past, the military has been regularly shaken by such scandals, although they tended to be limited to a single service at a time. The Navy’s Tailhook scandal in 1991 led to major changes in the service. In the late 1990s, Army sergeants abused trainees at Maryland’s Aberdeen Proving Ground and the service’s top enlisted soldier was court-martialed on charges that included sexual harassment.

But the near-simultaneous probes of uniformed sexual-assault preventers in the Air Force and Army may force Congress to act over Pentagon objections.

In the newest case, late Tuesday the Pentagon announced that an Army sergeant first class – an E-7 — who had served as a sexual-assault prevention coordinator at Texas’ Fort Hood is being investigated for “abusive sexual contact” and other misconduct.

“The soldier had been assigned as an Equal Opportunity Advisor and Sexual Harassment/Assault Response and Prevention (SHARP) program coordinator,” the Army said in a statement. “The accused was immediately suspended from all duties by the chain of command once the allegations were brought to the command’s attention. There have been no charges filed or preferred at this time.”

Predictably, Hagel expressed “frustration, anger, and disappointment over these troubling allegations and the breakdown in discipline and standards they imply,” Pentagon spokesman George Little said. He has ordered the services to “re-train, re-credential and re-screen” troops in such posts.

To lawmakers eager to dispatch reinforcements to help the military battle sexual assault, that is likely to sound too much like a broken record. It’s not likely to halt the push for wholesale changes in the way the military deals with this particular foe.