A divided US appeals court on Friday rejected plea agreements that would have allowed Khalid Sheikh Mohammed, the alleged architect of the September 11, 2001, attacks, and two co-defendants to plead guilty and avoid the death penalty. The 2-1 ruling by the US Court of Appeals for the District of Columbia Circuit derails efforts to resolve a military prosecution at Guantanamo Bay, Cuba, mired in over two decades of legal stalemate.

The plea deals, initially offered in 2024 and approved by the overseer of the Pentagon’s Guantanamo war court, were rescinded in August by then-Defense Secretary Lloyd Austin following backlash from Republican lawmakers. A military judge later ruled that Austin lacked the authority to cancel the agreements, a decision upheld by the US Court of Military Commission Review in December, prompting scheduled plea hearings. However, the Biden administration, followed by the Trump administration, challenged this ruling, leading the DC Circuit to pause proceedings and ultimately side with Austin’s authority.

In the majority opinion, Judges Patricia Millett (an Obama appointee) and Neomi Rao (a Trump appointee) stated that Austin “indisputably had legal authority” to withdraw the plea agreements. They emphasized that the Defense Secretary’s decision prioritized the “families and the American public” by preserving the possibility of full military commission trials. In contrast, Judge Robert Wilkins (also an Obama appointee) dissented, calling the ruling “stunning” and arguing that the court should have respected the military courts’ interpretation of their own rules.

Khalid Sheikh Mohammed, held at Guantanamo Bay since 2002, is accused of orchestrating the 9/11 attacks, which saw hijacked commercial planes crash into the World Trade Center and the Pentagon, killing nearly 3,000 people. His co-defendants, Mustafa Ahmed Adam al Hawsawi and Walid Muhammad Salih Mubarak bin ‘Atash, also faced the now-revoked plea deals. Matthew Engle, an attorney for bin ‘Atash, indicated that an appeal, potentially to the US Supreme Court, is under consideration. Representatives for Mohammed and Hawsawi, as well as the Pentagon, did not immediately comment.

The ruling prolongs the legal saga at Guantanamo, established under President George W. Bush to detain foreign militant suspects post-9/11, leaving the fate of these high-profile cases uncertain as the pursuit of military trials continues.