Updated 5:44 p.m.

Sen. Kirsten Gillibrand's (D-N.Y.) year-long fight to dramatically overhaul how the Pentagon handles cases of sexual assault and rape fell short Thursday afternoon when she failed to get the 60 votes needed to advance her proposal to a final vote.

Just 54 senators voted with her to advance a proposal that would take away from military commanders the power to refer serious crimes to courts-martial -- a proposal strongly opposed by Pentagon brass and several senior senators.

After the vote, Gillibrand said that reforms already adopted by Congress haven't gone far enough: "We know that the deck is stacked against victim of sexual assault in the military today – and today, sadly, we saw the same in the halls of Congress."

Even though she lost, Gillibrand is a big winner today. Here's why:

She bolsters her liberal credentials: Gillibrand was a moderate Upstate New York Democrat with a gold-plated score from the National Rifle Association when she was plucked from national political obscurity in 2009 to replace Hillary Rodham Clinton in the Senate. Facing a barrage of criticism from Democrats who considered her unworthy of the seat, she quickly sought ways to win over liberals by becoming a proponent of immigration reform. She was an early proponent of repealing the military's "don't ask, don't tell" policy and she reversed her position on gun control. Five years later, she's lost a big battle against the Pentagon bureaucracy -- which, let's face it, isn't held in great standing with many liberals. Her political makeover has placed her on the short list of Democrats who could run for president in the coming years.

She's boosted her standing in the Senate: Never again will colleagues be able to dismiss her as an ambitious lightweight, as many did when she first arrived in 2009. (Who said ambition was a bad thing in the Senate, anyway?) Over the course of the past year, Gillibrand has presented her colleagues with reams of information detailing examples of abuse and rape ignored by military commanders. She's coaxed victims into meeting individually with skeptical members -- who have emerged from the meetings with a changed mind.

Most impressively, she stitched together a coalition unlike most ever assembled in the modern Senate. Gillibrand can boast of having on one stage some of the most conservative and liberal senators: Charles E. Grassley (R-Iowa), Ted Cruz (R-Tex.), Rand Paul (R-Ky.), Dean Heller (R-Nev.), Richard Blumenthal (D-Conn.), Barbara Boxer (D-Calif.) and Hirono all regularly attended her press conferences. She and Paul even shed tears together at a recent event as they listened to victims of assault describe their ordeals. Gillibrand found 54 colleagues of both parties who agreed with her. In a chamber seriously lacking in bipartisanship, that's a notable accomplishment.

She bolsters her standing with women and the gay community: Gillibrand has been working for several years to elect more Democratic women to office through her "Off the Sidelines" campaign. The effort has raised millions of dollars for several of her colleagues, including Sens. Tammy Baldwin (D-Wis.), Mazie Hirono (D-Hawaii) and Rep. Tulsi Gabbard (D-Hawaii). Having failed to advance a bill designed to bolster the protection of women serving in uniform, she will earn plaudits from women's groups.

Just a few hours after the vote, Gillibrand sent her campaign donors a message, entitled, "Never quit."

"Heartbreakingly, we fell five votes short of overcoming the 60 votes needed to break a filibuster, despite earning support from a majority of the Senate," she said, adding later: "Words can’t adequately express my disappointment – but I will never quit."

The message didn't include an explicit ask for money -- but it didn't need to.

The senator also will earn even more support from the gay community, which is equally concerned about assault and rape in the ranks. While a greater percentage of women have been the victims of assault or rape, there is a larger overall number of men who have been assaulted or raped while serving in the military, according to Defense Department statistics.

But there's an important caveat regarding Gillibrand's standing with women: The recent debate exposed serious policy disagreements between the Senate's now-record 20 women. While 16 of the women supported Gillibrand's proposal, three did not, including Sen. Claire McCaskill (D-Mo.), who emerged as a frequent and vocal critic of her plan. Several aides familiar with the debate said that the ordeal has frayed relations between the 20 women, especially between Gillibrand and McCaskill. And senators of both parties and genders have openly expressed concern that the fight has distracted from the fact that Congress took steps in the past year to enact more than 30 changes in the military's legal system to address the rise of assault and rape.

She can say "I told you so" if the Pentagon doesn't fix the problem: Gillibrand chairs a Senate Armed Services subcommittee on military personnel, giving her direct oversight of how the Pentagon is handling cases of assault and rape. She vowed Thursday to continue the fight, saying that "I will never quit" on the victims of assault and rape who pushed for reforms. If data in the coming years continue to show that the number of assault and rape cases remains high, Gillibrand will have a credible case to make to colleagues that it's time to enact the bold reforms she proposed.

Gillibrand told reporters after the vote Thursday that "Many people said to me, 'Kirsten, I’m going to watch this and if it doesn’t get better in the next six months, I’m with you next time.'"

It's a good bet there will be a next time.