A broad cross-section of the U.S. Senate renewed its push Wednesday to dramatically overhaul how the Defense Department handles allegations of sexual assault even as the proposal's lead sponsor admitted she is still well short of garnering the votes needed to pass the measure.

Sen. Kirsten Gillibrand (D-N.Y.) forcefully defended her plan to remove decisions on whether to prosecute cases of sexual assault, rape and similar crimes from the military chain of command by establishing an independent team of military prosecutors to review the cases. The proposal is expected to be introduced as an amendment to the annual defense authorization bill whenever debate on the omnibus measure begins in the next two weeks.

Flanked by seven of her colleagues from both parties at a news conference on Capitol Hill, Gillibrand said there has been "zero accountability" in the ranks for dealing with allegations of assault and rape, despite two decades of assurances by military leaders that there is "zero tolerance" for such crimes.

"Critics say moving these decisions out of the chain of command will diminish good order and discipline. Well I have news for you -- with 26,000 cases of sexual assault, rape and unwanted sexual contact last year alone, we don't have the good order and discipline that our military needs," Gillibrand said.

The Department of Defense has estimated that as many as 26,000 service members were the targets of unwanted sexual contact last year, although only 3,374 incidents of sexual assault were reported. Gillibrand and other lawmakers have seized on those figures as evidence that significant reforms are long overdue.

"This proposal will strengthen morale," said Sen. Charles E. Grassley (R-Iowa). He is one of several GOP co-sponsors, including Sens. Lisa Murkowski (R-Alaska), Rand Paul (R-Ky.) and Ted Cruz (R-Tex.).

"This crusade for justice is a welcome breath of fresh air," Paul said as he credited Gillibrand for methodically wooing support from colleagues of both parties.

Paul said the argument for overhauling the military's handling of such cases is based on a simple question: "Should you have to report to your boss if you've been the victim of a crime?"

In an emotionally-charged moment, Gillibrand and Paul shed tears as two former Marines, Ben and Ariana Klay, detailed how she was assaulted, faced retribution for reporting the assault and endured 15 hours of "degrading testimony" during a military trial. Senators gasped as Ben Klay described how prosecutors read the definitions of several sexually degrading terms into the public record during closing arguments of his wife's trial.

Despite the emotion surrounding the issue, Gillibrand said her proposal has just 46 co-sponsors, still short of the votes that will be needed.

Exactly how many votes will be required is still in dispute. Amendments directly related to military policy are usually permitted to pass with a simple majority vote. But Sen. Carl Levin (D-Mich.), who chairs the Senate Armed Services Committee, suggested to reporters this week that Gillibrand's bill will require at least 60 votes because it is considered a controversial proposal.

The final decision on how to proceed rests with Senate Majority Leader Harry M. Reid (D-Nev.), who aides said has yet to determine how many votes will be required.

Even if Reid decides that the proposal only needs 51 votes to pass, several GOP senators have suggested they may filibuster the amendment in opposition.

Sen. Barbara Boxer (D-Calif.), who was one of the proposal's earliest supporters, said Levin "is wrong" to be suggesting that the Gillibrand proposal will require a filibuster-proof majority to pass. "The victims deserve an up-or-down vote, they don’t deserve to be filibustered," she said.

Boxer and Sen. Lindsey O. Graham (R-S.C.) are pushing a separate proposal to revamp how the military handles Article 32 hearings, or proceedings held to determine whether a court-martial is warranted. The proposal has several co-sponsors from both parties, including Gillibrand, and is expected pass easily when introduced as an amendment to the defense bill.

"While we have a very important debate, critical debate on whether to take prosecutions of sexual assault out of the chain of command – and I feel strongly we have to – whether we do that or we don’t do that, we have to reform Article 32," Boxer said.

Aides said her proposal was prompted by recent news reports about the pre-trial hearing for two former Navy football players now facing court-martial for allegedly sexually assaulting a female midshipman. During the hearing, the players' defense attorneys grilled the 21-year-old accuser for more than 20 hours about her medical history, motivations, whether she wore underwear, how she danced and how she performed oral sex.

The Gillibrand and Boxer amendments are just two of hundreds of proposals expected to be introduced in the coming days on a wide range of issues related to military policy. Aides expect there will be several proposals introduced regarding the treatment of terrorism detainees at the U.S. detention facility at Guantanamo Bay, Cuba, and in response to recent revelations about the spying practices of the National Security Agency.

Correction: A previous version of this article suggested that Sen. Claire McCaskill (D-Mo.) has introduced an alternative to the Gillibrand proposal. Those proposals, which include making it more difficult to reverse convictions for sexual assault crimes and requiring dishonorable discharges for people convicted of those crimes, are already part of the defense authorization bill.

Updated at 4:40 p.m.