Supreme Court rejects plea‑deal appeal by alleged 9/11 mastermind

what happened

The Supreme Court issued a per curiam decision on Oct 19, 2026, rejecting the petition filed by Khalid Sheikh Mohammed and two fellow Guantanamo detainees. The men had asked the Court to enforce a plea deal signed in 2024 that would have given them life sentences instead of facing capital charges. The Court’s brief order affirmed the lower‑court ruling that the government could nullify the agreement after Defense Secretary Lloyd Austin withdrew his support.

who is involved

• Khalid Sheikh Mohammed – alleged ringleader of the September 11 attacks, detained at Guantanamo Bay since 2006.
• Mustafa Ahmed al‑Hawsawi – Saudi national, also held at Guantanamo, accused of financing the plot.
• Walid bin Attash – Yemeni national, Guantanamo detainee, charged with planning the attacks.
• Lloyd Austin – U.S. Secretary of Defense who overrode the plea deal in 2024.
• U.S. Supreme Court – issued the denial of the appeal.
• U.S. Court of Appeals for the D.C. Circuit – earlier ruled the government could discard the deal.

what happens next

With the appeal dismissed, the three men are set to stand trial before a military commission in 2028, a date the court system has already earmarked. The commission will decide whether to pursue the death penalty, a possibility highlighted in the original plea negotiations. The government has said the trial will proceed under the rules governing enemy‑combatant prosecutions, and no further legal avenues appear open to the defendants at this stage.

key numbers

The Supreme Court’s denial removes the final legal barrier to a trial that could culminate in a death‑penalty verdict, a prospect the Pentagon has said remains within its authority.

The case also underscores the lingering legal complexities of the post‑9/11 era, including disputes over the authority of defense officials to overturn negotiated settlements and the ongoing role of military commissions in adjudicating terrorism‑related charges.