Among the changes to military personnel policy included in the fiscal 2015 defense policy law signed Dec. 22 are provisions to change the way the Pentagon handles sexual assault and rape cases.

The changes grant additional protections for victims and revamp administrative and legal procedures to ensure that commanders and investigative bodies take allegations of sexual assault seriously and properly handle criminal procedures.

While the new measures fall short of the step sought by some lawmakers and advocates — removing the authority of some commanders to decide whether a sexual assault case should be prosecuted in court — the changes overhaul military rules of evidence and give victims more say in how their cases are pursued.

"This legislation further builds on our sweeping, bipartisan reforms that are changing how the military handles sexual violence," said Sen. Claire McCaskill, D-Mo., a key proponent of overhauling the Defense Department's sexual assault prosecution procedures.

According to Pentagon estimates, military sexual assaults have surged in the past decade, peaking in 2012 at an estimated 26,000 cases, a 37 percent increase from the previous year. In addition, a number of high-profile cases, including allegations that a soldier was running a prostitution ring at Fort Hood, Texas, and charges of sexual battery against the head of the Air Force's sexual assault prevention programs (the officer was later acquitted), pushed Congress to make several legislative changes to address the problem and forced the Pentagon to improve its sexual assault prevention programs and reporting procedures.

Pentagon officials reported in December that the estimated number of sexual assaults is down to 20,000 while reports increased in 2014 by 8 percent to 5,983 — a rise they say shows that progress is being made, both in preventing attacks and encouraging victims to come forward.

Still, with fewer than one-third of the total assaults reported, and a sense that the estimates are low since sexual assault is a crime that is commonly under-reported, a bipartisan coalition of legislators in the House and Senate pushed for further reform in the annual defense policy bill.

The new law requires that commanding officers' fitness reports specify whether the commander has established a unit climate amenable to reporting sexual assault allegations; gives victims a say in whether the crime should be prosecuted in civilian or military court; throws out the "good soldier" defense, a tactic that allowed defendants to cite their military character to demonstrate the likelihood of innocence; and provides victims with special counsel.

The law also allows victims to petition the court if they disagree with the outcome of a case; specifies which medical personnel should conduct forensic sexual assault exams; lets victims who were dismissed from the military and were victims of sexual violence to appeal their discharges to their services' Board for Correction of Military Records; and establishes a Defense Advisory Committee on Investigation, Prosecution and Defense of Sexual Assault.

Despite the changes, Sen. Kirsten Gillibrand, D-N.Y., said she will continue to push for sexual assault and rape cases to be handled by independent military prosecutors with expertise in these crimes.

Before the defense authorization law was signed, Gillibrand stood with a diverse group of senators, including fellow Democrat Barbara Boxer of California and Republicans Rand Paul of Kentucky and Ted Cruz of Texas, vowing to reintroduce her bill, the Military Justice Improvement Act.

Gillibrand said the legislation is still needed because victims continue to face retaliation and retribution after reporting alleged incidents and still are reluctant to come forward.

In statement following the defense bill's passage, Gillibrand said she voted against the law because it contained a provision to arm Syrian rebels, but she addressed the bill's reforms to military sexual assault procedures, including a provision she introduced that adds protections for victims' mental health records, tightening privacy rules to keep these records from being used in a court-martial.

"There are priorities of mine that I have fought hard for in this bill and I am proud they are in the final bill," Gillibrand said.

President Obama signed the $585 billion Defense Authorization Act on Dec. 22, funding, among other things, ongoing operations in Syria and Iraq, a 1 percent pay increase for military personnel and limits on the growth of housing allowances.