WASHINGTON – Sen. Kirsten E. Gillibrand’s crusade to crack down on sexual assaults in the military got a big boost Tuesday from what may seem, at first, the unlikeliest of sources: the nation’s two most prominent tea party senators.

Sens. Rand Paul of Kentucky and Ted Cruz of Texas – both possible Republican presidential candidates in 2016 – joined the New York Democrat to announce that they strongly back her proposal to allow trained military lawyers, rather than commanders, decide whether to prosecute complaints about sexual assaults in the armed services.

“Some say we have no bipartisan cooperation around here, and I disagree,” Paul said. “I think this is a great example of how people from both sides come together and are willing to work on a problem and look honestly at, you know, what the problem is.”

Paul, like Cruz, said he decided to side publicly with Gillibrand on the issue after hearing her argue that the current system – when commanding officers decide whether to pursue sexual-assault cases – leaves many victims too intimidated to come forward.

Lauding “Sen. Gillibrand’s exceptionally passionate and able advocacy,” Cruz said: “The most persistent problem we’ve seen is an unwillingness, an inability to report these crimes, that the victims of sexual assault, for whatever reason, have consistently remained reluctant, afraid to come forward and report the crimes. And there can be no prosecution, there can be no deterrence, if we don’t have reporting of crimes.”

The support of Paul and Cruz is both a huge boost to Gillibrand’s effort, as well as to New York’s junior senator herself and her unlikely new Republican partners.

Aides to Gillibrand think the support of two strong conservatives makes it more likely that others will also sign on to her effort on the sexual-assault issue, which will come to a head on the Senate floor later this year.

Beyond that, appearing with two stars of the tea party movement brings Gillibrand increased national attention at a time when some polling firms are starting to include her on their lists of possible candidates for the 2016 Democratic presidential nomination, even though she has disavowed any interest in the race.

And for Paul and Cruz, signing on to Gillibrand’s effort allows them to broaden their political appeal beyond the conservative base, particularly with women who have voted increasingly Democratic in recent years.

“You know, I try not to look at issues from a partisan view. I’m sure I do sometimes, but I try not to,” Paul said.

“As a physician, I look at problems, and I try to find solutions. I’m concerned, you know, about justice. And I want it to occur in the military for the victims, as well as potentially those accused.”

Gillibrand stressed that her proposal was written in response to what victims of military sexual assault told her: that they’re reluctant to report crimes to their commanders but would place far more trust in trained prosecutors.

“So this is not a Democratic idea. It is not a Republican idea. It is a good idea that meets the needs of the victims, creates transparency and accountability, and creates the needed objectivity that this issue deserves,” she said.

It’s an idea, though, that faces steadfast opposition from the Pentagon’s top brass.

“Reducing command responsibility could adversely affect the ability of the commander to enforce professional standards and, ultimately, to accomplish the mission,” Army Gen. Martin E. Dempsey, chairman of the Joint Chiefs of Staff, told the Senate Armed Services Committee last month.

That panel’s chairman, Sen. Carl M. Levin, D-Mich., has steadfastly sided with the military on the issue.

“If you remove the chain of command, you are taking away the club that they need to change the culture,” Levin told reporters Tuesday at a breakfast sponsored by the Christian Science Monitor. “It’s commanders who make it work. They give orders.”

Levin said the changes that he recently pushed through his committee – which include moving the decision on whether to prosecute up to the level of colonel – will make it easier for victims of sexual assaults to report such crimes without disturbing the chain of command.

In response, Gillibrand said Levin’s proposal doesn’t address the fundamental issue facing victims of sexual assault in the military.

“They don’t trust the chain of command,” she said.

“And so if the victims do not trust the chain of command, they will not report these cases. If they’ve witnessed other people reporting being retaliated against, if they’ve witnessed other people being shoved out of the military because they’ve reported these crimes, they will not trust the system that the chain of command has put into place.”

So far, though, Levin has won the political battle on the issue. By a 17-9 vote, the Armed Services Committee last month backed his approach to the issue over Gillibrand’s.

Now, though, Gillibrand plans to bring her bill up on the Senate floor as an amendment to a must-pass defense authorization bill. Her measure already has 33 co-sponsors, and Sen. Charles E. Schumer, D-N.Y., plans to support it even though he is not listed as a co-sponsor.

Gillibrand and her allies hope to build support for the measure with a hard reliance on the facts, including the findings of a recent Pentagon report that estimated there were 26,000 sexual assaults in the military last year but that victims reported only 3,374 of them and that only about 300 cases went to trial.

Then there’s the fact, highlighted on a handout at Tuesday’s news conference, that the sexual-abuse problem has continued through the tenure of seven consecutive defense secretaries, dating from 1992, who all swore to a “zero tolerance” or “no tolerance” policy regarding such crimes.

“Enough with the empty promises,” said Sen. Barbara Boxer, D-Calif.

Cruz, meanwhile, noted that several of America’s allies, such as Britain and Israel, have made exactly the change that Gillibrand is suggesting and have seen an increase in the reporting of sex crimes in the military but no negative effect on military effectiveness.

“I’m proud to see the Senate working to fix this problem,” Cruz said, “to make sure that we protect every young man and every young woman who signs up to defend our nation, to defend our liberties and to make sure that they have a safe, secure environment where they can trust their fellow soldiers and be secure from any threat of sexual assault.”