WASHINGTON -- A sometimes contentious congressional panel yesterday heard a former military prosecutor call for the end to the system of military commissions used to try terrorist suspects now held at Guantanamo Bay.

"The military commission system really is beyond repair," said Lt. Col. Darrel Vandeveld, an Army reserve member who, in civilian life, works as a state prosecutor from Erie.

At one point, Lt. Col. Vandeveld oversaw a third of the cases being prepared for the more than 200 men, designated "enemy combatants," held at a special prison camp at the U.S. Naval Base at Guantanamo.

He said he asked to be reassigned as a prosecutor after discovering that one of the defendants he was assigned to prosecute was taken captive at age 16 and tortured.

Yesterday's hearing was conducted by the House Judiciary Committee subcommittee on the Constitution, Civil Rights and Civil Libertites. While many subcommittee hearings are sparsely attended, yesterday's drew a surprisingly large turnout from members, including Judiciary Chairman John Conyers, D-Mich., and ranking Republican member, Lamar Smith of Texas.

A quintet of witnesses largely criticized the commissions system as a failure, several noting that to date only three prosecutions have been completed.

One witness, Thomas Joscelyn, a senior fellow at the conservative Foundation for Defense of Democracies, recommended reforms in the present commission system. Even his testimony was tempered by concerns over the process, while he insisted that "there is no material dispute over the high value detainees' importance."

Mr. Joscelyn, who served as terrorism advisor to former New York Mayor Rudolph Giuliani during the 2008 Republican primaries, speaking before he testified, said he had little doubt that some reforms in the system must be made.

"Nobody's defending the military commission system as it is," he said.

Unlike federal criminal prosecutions or military courts martial, the commissions have allowed hearsay evidence and testimony taken under duress -- in some cases sleep deprivation or exposure to extreme temperatures and humiliation techniques.

"I think the real issue here is do we really believed in due process? Do we really believe in the search for the truth? Or do we want to take political advantage?" said Rep. William Delahunt, D-Mass.

"What we're hearing today is a continuation of the assault by the American political left," countered Rep. James Sensenbrenner, R-Wisc., the ranking minority member of the subcommittee.

Panel members at points engaged in debate with each other over everything from the reliability of evidence designating some detainees as terrorists to what to do with members of the Uighur community -- persecuted Chinese Muslims picked up in Afghanistan. Fifteen of the 22 held were later determined not to have been enemy combatants and their detention a mistake.

Lt. Col. Vandeveld said he became the seventh military prosecutor at Guantanamo to leave his post after becoming disillusioned by a system he says revealed itself in the case of detainee Mohammed Jawad.

Lt. Col. Vandeveld said Mr. Jawad, who was 16 at the time he was detained by U.S. forces, confessed under torture, twice attempted suicide and underwent abusive interrogations and never received evidence Lt. Col. Vandeveld said might have cleared him of accusations.

"In fact, the military had obtained confessions from at least two other individuals for the same crime," Lt. Col. Vandeveld to the committee.

Lt. Col. Vandeveld's decision to quit as a prosecutor was the subject of a May 10 story in the Post-Gazette and his congressional testimony was in large measure a restatement of his earlier arguments that the military commission system -- which bypasses both traditional military courts and the Geneva Conventions -- threatens to undermine U.S. credibility.

Chairman Jerrold Nadler, in opening remarks left little doubt that he favored the elimination of the commissions and one witness, U.S. Rep. Adam Schiff, D-Calif., called on Congress to enact regulations that would move the prosecution of enemy combatants to military courts martial under the Uniform Code of Military Justice.

Lt. Col. Vandeveld, an Army reservist who has served in Iraq, Bosnia and Afghanistan, agreed with that assessment.

"The military commissions cannot be fixed because their very creation ??? can now be clearly seen as an artifice, a contrivance, to try to obtain prosecutions based on evidence that would not be admissible in any civilian or military prosecution anywhere in our nation," Lt. Col. Vandeveld said.

The Senate Armed Services committee currently is crafting legislation to reform the system, but both Lt. Col. Vandeveld and another military lawyer who defended a Guantanamo detainee said the system cannot be repaired.

"Nobody knows what the new mousetrap is going to look like. All we know is it's going to be designed by the prosecutors," said Barry Wingard, an Air Force reservist from Dormont and Allegheny County public defender who was assigned to defend a Kuwaitee detainee.

At present, the Senate is considering changes that would continue to allow the admission of hearsay evidence -- testimony not directly provided by a witness. Lt. Col. Wingard said that one of the major problems in the case of his client, Fayiz Al-Kandari.

Mr. Al-Kandari, a Kuwaiti citizen, had traveled to Afghanistan in 2001 when he was detained by Northern Alliance troops who handed him over to American troops in return for a cash reward.

"All the local warlords set out to do bounty hunts for Arabs that were in Afghanistan at the time," Lt. Col. Wingard said.

Lt. Col. Wingard said his client, the son of a wealthy Kuwaiti family, had traveled to Afghanistan to do charity work required of his Muslim faith. He said Mr. Al-Kandari was subjected to sleep deprivation and subjected to extreme cold while strapped naked to a floor while at Guantanamo. Prior to his arrival at Guantanamo, Lt. Col. Wingard said his client was beaten with a chain.

"He was given the full works, an enhanced interrogation," Lt. Col. Wingard said.

Since objecting to the commission system, the Air Force promoted him from the rank of Major to Lieutenant Colonel, evidence, he said, that the military itself is displeased with the commissions trial system imposed on it by the Department of Justice.

"The military's never been behind anything but the Geneva Convention," Lt. Col. Wingard said.

Military prosecutors have so far declined to press a case against Mr. Al-Kandari. He remains in custody at Guantanamo.

Lt. Col. Vandeveld, discussing his own experiences in the Jawad case as well as his disillusion with the military commissions, asked committee members to contemplate "the kind of role reversal that senior military officers routinely consider.

"Imagine that U.S. soldiers captured on the battlefield were, today, being subjected to the type of trial proceedings that we plan to set up through these military commissions. Imagine that our service members had been tortured or abused, and that the commissions hearing their cases allowed into evidence obtained through coercion," he said. "How would our government react to such trials?"