Retired US Army general, John D Altenburg Jr, who is overseeing the trials of at least four Guantanamo Bay detainees, overnight dismissed three of the six officers who would pass judgment in those cases, after defence lawyers claimed potential bias.
But General Altenburg refused requests to dismiss presiding officer US Army Colonel Peter E Brownback.
Colonel Brownback had been challenged by both prosecutors and defence lawyers over his relationship with General Altenburg.
The pair worked together in Fort Bragg, North Carolina.
Col Brownback spoke at Gen Altenburg’s retirement roast and attended his son’s wedding, and Col Brownback’s wife worked in Gen Altenburg’s office.
Replacement officers will not be appointed for the trails, which will proceed next month.
Terry Hicks said dismissing the officers would not make his son’s trial any fairer while Col Brownback was still in charge.
“Whatever way you look at it, whether there’s two, 30 or 20 (officers), it’s still an unfair system,” Mr Hicks said.
“It’s a system that’s set up to go against these people (terror suspects) anyway.
“Now that they’ve got rid of three, I just think this has given Brownback his own way.
“When I was there last time (for commission hearings), he did most of the talking anyway.
“He’s only got two with him to convince now, and they haven’t had any legal training whatsoever.”
In a 28-page ruling, General Altenburg denied the challenge brought by lawyers for David Hicks and Salim Ahmed Hamdan that Colonel Brownback would not be fit to serve because of his friendship with him.
He said social and professional relationships between appointing officers and judges was customary in the military, but military law protected against bias by making it a criminal offence to attempt to influence a military court or any of its members.
He also cited Colonel Brownback’s testimony that as a military judge he had on six or seven occasions acquitted people General Altenburg had referred to court martial, and had reversed General Altenburg’s personal rulings in several cases.
In a military hearing at Guantanamo Bay, Cuba, in August, David Hicks pleaded not guilty to conspiracy, attempted murder and aiding the enemy.
Motion hearings in the case will start next month.
Adelaide-born Hicks was captured among Taliban forces in Afghanistan in December 2001 and was transferred to Guantanamo Bay a month later.