In another case, a judge approves the release of a captive’s interrogation video showing the blurred face of an American agent. But a federal prosecutor on loan to the Pentagon withholds it “out of an abundance of caution.”

Even as the U.S. government edges toward full-blown, war-crimes trials by military commission here, with more hearings next week, all sides are grappling with what information can be made public and what must be kept secret.

Consider: A new courtroom here sequesters Pentagon-approved spectators behind a soundproofed window. If a terror suspect tries to shout about his treatment in U.S. custody, a military censor can mute the audio feed that observers hear.

Under rules that protect interrogation techniques, the Pentagon’s war court won’t let the reputed 9/11 architect, Khalid Sheik Mohammed, say he was waterboarded - something the CIA director, Air Force Gen. Michael V. Hayden, confirmed on Feb. 5.

Pentagon officials defend the Military Commissions as engaged in a delicate balancing act — working to mete out justice to war-on-terrorism captives without exposing U.S. intelligence tactics and personnel to public scrutiny.

As long as there is an al Qaida, they argue, such information could be used to hurt Americans or their allies.

At the same time, the commissions architects have long pledged that they will be open to international scrutiny.

”We can’t disclose classified information. We can’t disclose privacy information,” the war-court legal advisor, Brig. Gen. Thomas Hartmann, said in an interview.

Unlike in federal courts, jurors at commissions are U.S. officers. In some circumstances, they can see or hear evidence that is shielded from the public.

Hartmann argues that a commissions defendant gets the same rights as a soldier at a court-martial — among them an American military lawyer to defend him, and a presumption of innocence.

Attorneys for the Guantánamo captives disagree. They argue that, unlike civilian or military justice systems, the rules favor the government and permit evidence gleaned from abusive interrogations.

The Pentagon prosecutor has accused six of the 280 or so captives here of being 9/11 conspirators. If Hartmann’s boss approves the death-penalty charges, conviction could end in their execution.

Meantime, the American Civil Liberties Union is suing the Bush administration in federal court to unseal portions of transcripts from military hearings, in which Mohammed and others now held at Guantánamo lay out allegations of torture.

‘There is no remotely legitimate basis for the government to withhold these prisoners’ account of their mistreatment,” says Ben Wizner, an ACLU staff attorney and sometime war-court observer.

”I would simply note that governments don’t censor information to conceal lies,” Wizner said. “They censor information to conceal the truth.”

The military says these trials — the first war-crimes tribunals since World War II — are unprecedented because they risk talking about tactics while the nation is at war. Hence, the need for secrecy.

Critics say such secrecy could strip the military commissions of legitimacy.

When he was chief prosecutor, Air Force Col. Moe Davis once likened Guantánamo detainees to ”vampires” fearful of the bright light of American justice.

But then in October he resigned his post, protesting what he called political pressure to speed up the cases — and sacrifice transparency. Rushing them, he said, risks using secret evidence or confessions gained through tough interrogation tactics.

With time, he said in a recent interview, the prosecution can build public cases using evidence from before Mohammed’s capture — and before he was waterboarded by the CIA.

”If they want to take KSM out and shoot him, I would have no problem with that. Fine,” he said, using Mohammed’s initials. “If they want to call it military justice, you’ve gotta give him a fair trial.”

Meantime, the Pentagon has created a labyrinth of bureaucracy that shields from public disclosure some of the inner workings of the commissions.

Reporters and other observers must agree to a series of regulations that have no counterpart in the civilian court system. Journalists are forbidden, for example, to report anything uttered in court that a Pentagon security officer declares “protected information.”

Earlier this month, a Navy defense lawyer mistakenly spoke the last name of the battlefield commander at the capture of a 15-year-old Canadian in Afghanistan. Reporters were instructed to identify him only as ”Lt. Col. W.,” or risk being banned from covering the court.

In the case of the interrogation video, Judge Keith Allred, a Navy captain, approved its release in December. It shows Osama bin Laden’s driver, a Yemeni in the garb of a bushy-bearded South Asian, being questioned soon after his capture by U.S. allies in November 2001 in Afghanistan.

The driver’s attorney, Lt. Cmdr. Brian Mizer, believes it is the first recorded battlefield interrogation of an alleged al Qaeda associate during the U.S. invasion meant to topple the Taliban, dismantle al Qaeda and capture bin Laden and other 9/11 plotters.

But Army Reserves Maj. Bobby Don Gifford, a federal prosecutor on loan to the Pentagon as a public-affairs specialist, said he chose to withhold it from public view ”out of an abundance of caution,” and offered a cascade of explanations in a March 17 e-mail:

Gordon England, deputy secretary of defense, issued a memo banning the release of Guantánamo detainee photos. The Pentagon is bound by the Geneva Conventions not to humiliate detainees, it said, and “We respect the dignity of all persons.”

Then this, ‘Geneva Conventions prohibit the use of images that could be deemed `propaganda,’ and because I don’t know or can control what others may do with it — I don’t want to be in the position of violating the law — thus I’m exercising caution.”

Under the system, the Pentagon says the Office of Military Commissions — not the judge — has the last word on what the public can see.

In a November response to a written protest by attorneys for The New York Times and other news organizations, the commission deputy legal advisor, Michael Chapman, explained it this way: Military judges are charged with “the delicate balance of providing for the public interest in the commission proceedings, protecting the rights of the accused, maintaining witness privacy, securing classified or sensitive information and ensuring the interests of justice are appropriately respected and protected.”

Despite the controls, some of the trial evidence is popping up elsewhere.

A video clip of Canadian captive Omar Khadr allegedly learning to plant mines as a teen in Afghanistan turned up on 60Minutes last year. Yet the Pentagon has so far declined to provide reporters covering the commissions with copies of it, saying they don’t know who leaked it — or how.

Khadr’s Pentagon-appointed defense attorneys have consistently complained about a lack of transparency in the process. Khadr is accused of throwing a grenade in a 2002 firefight in Afghanistan that fatally wounded a sergeant with the U.S. Special Forces.