(CNN) — President Joe Biden on Friday ordered a historic change to the Uniform Code of Military Justice by transferring key decision-making authorities outside the military chain of command in cases of sexual assault, domestic violence, child abuse, murder and other serious crimes.

The order, which the administration is calling “the most significant transformation of the military justice system since the UCMJ was established in 1950,” officially implements changes passed by Congress as part of fiscal year 2022’s National Defense Authorization Act (NDAA), and comes two years after an independent review commission on sexual assault in the military, formed by Defense Secretary Lloyd Austin, recommended moving prosecution of sexual assault in the military outside the chain of command.

Key among the changes in the order is the establishment of rules to govern the newly formed Offices of Special Trial Counsel (OSTC) which, composed of a panel of independent military prosecutors, would make prosecutorial decisions involving sexual assault and other violent crimes.

On a call with reporters previewing the executive order, a senior administration official called the move “a turning point for survivors of gender-based violence in the military.”

“These changes follow decades tireless efforts by survivors, advocates and members of Congress to strengthen the military justice systems response to gender-based violence,” the official said. “As Secretary Austin has said many times, this is a leadership issue, and we believe this historic order demonstrates that leadership.”

In a statement following the signing, New York Democratic Sen. Kirsten Gillibrand – who, along with Republican Sen. Joni Ernst of Iowa, led a bipartisan push in Congress to remove prosecution of sexual assault from the military chain of command – applauded Friday’s executive order, writing while it may take time to see results of the new system, “these measures will instill more trust, professionalism, and confidence in the system.”

The senior administration official took care to acknowledge Gillibrand’s work on the issue ahead of the order’s signing, calling her “a leader for decades in calling attention to the need to reform the military justice system in a way that’s fairer and more just – particularly for sexual assault survivors.”

According to the administration, Gillibrand was influential in leading the charge to expand the scope of crimes covered by the independent counsel beyond sexual assault to also include murder, manslaughter and kidnapping – changes ultimately reflected in Friday’s executive order.

Biden signed the order Friday morning before departing for Maine. The text of the executive order was posted on whitehouse.gov and a White House official said the full changes to the Manual for Courts Martial will be published in the Federal Register, which may take a few days.

In addition to formalizing the rules governing the OSTC, Friday’s executive order will also establish prosecutorial decisions made by special trial counsel as wholly independent from the chain of command; update procedures the administration says will ensure protections for victims before, during, and after court martial proceedings; and alter the court-martial sentencing system to “promote uniformity and fairness.”

“What this executive order does is it really creates the rules of the road for an absolutely brand-new class of independent military prosecutors, and creates the independent authority and the command reporting structure of the Offices of Special Trial Counsel, that very importantly – and this was in the 22 NDAA – will report without intervening authorities directly to the civilian service secretaries of each military service,” a second official said Thursday.

Under the 2022 NDAA, the new changes are set to take effect by December 27, 2023 – but, per the administration official, the OSTC has already been established within the Department of Defense and is in the process of staffing up.

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