The man accused of planning the 9/11 attacks appeared at a hearing for his upcoming trial in a green camouflage vest covering his white robes, intended to bolster his claim he was a prisoner of war, subject to the Geneva Conventions.

GUANTÁNAMO BAY NAVY BASE, Cuba — Khalid Sheik Mohammed wore a $39.99 camouflaged vest to the war court Wednesday, a small victory for the accused architect of the Sept. 11 attacks awaiting his death-penalty terror trial.

Three U.S. sailor guards sat just feet away from him, in the latest Navy battle dress, demonstrably distinctive from the man accused of masterminding the worst terror attack in U.S. history.

Mohammed’s RothcoVintage Woodland Camo Ranger Vest — on sale for $39.99 in Sears’ website catalog — accessorized his traditional, flowing white garb.

U.S. Army Capt. Jason Wright argued that Mohammed had a Geneva Conventions right to don camouflage because he wore similar garments as a member of the U.S.-backed mujahedeen holy-warrior movement in Afghanistan, and also in Bosnia.

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The Pentagon prosecutors protested the clothing choice, too, arguing it might make a mockery of the military tribunals.

The attire is part of Mohammed’s effort, through Pentagon-paid lawyers, to communicate to the court that he considers himself a legitimate combatant entitled to Geneva Convention status as a prisoner of war. Once he got to Guantánamo from years in CIA custody, Mohammed described himself as a revolutionary — like George Washington.

The prosecution calls him a terrorist as alleged architect of the 2001 hijackings of four aircraft that left nearly 3,000 people dead in New York, Pennsylvania and at the Pentagon. His four co-defendants allegedly trained, financed or helped arrange travel for the 19 hijackers.

This week, lawyers are doing the spadework to prepare for trial, arguing motions on defense resources and government secrecy in the first hearings since Mohammed and four other men were formally charged on May 5.

The prison camps chief, Navy. Rear Adm. David Woods, refused to let Mohammed wear the vest to court in May.

Mohammed has been known for flamboyant behavior, singsong outbursts in Muslim prayer in 2008 hearings, at which he emerged from years in secret CIA prisons that included 183 rounds of water boarding with a massive white beard evocative of Rip Van Winkle.