The Senate Thursday rejected a bill aimed at curbing military sexual assault by stripping military commanders of prosecutorial authority.

The vote was 55-45, and fell short of the approval of 60 lawmakers needed to end debate on the legislation authored by Sen. Kirsten Gillibrand, D-N.Y.

Gillibrand’s bill would have given the power to prosecute sexual assault cases to independent military lawyers operating out of the alleged victim’s chain of command.

Gillibrand authored the bill in response to testimony from sexual assault victims in the military, who said their cases were not taken seriously by commanders. Gillibrand said her bill would provide better protection to victims by turning sexual assault cases over to independent prosecutors.

“Disappointed we were unable to overcome a filibuster today,” Gillibrand tweeted after the vote. “I will not stop fighting for survivors of military sexual assault.”

Republicans and some Democrats said they believed the Gillibrand measure would remove too much power from military commanders and interfere with the chain of command.

After defeating the Gillibrand measure, the Senate voted to move ahead with a bill authored by Sen. Claire McCaskill, D-Mo., which would require commanders confronted with sexual assault cases to consult with their Staff Judge Advocates and would require a civilian review of cases that commanders decide not to prosecute. McCaskill's bill would also eliminate the “good military character” clause that commanders can use when deciding whether to prosecute someone for a sexual assault.