Alexandria, Va. ? A federal judge dealt a severe setback to the only U.S. prosecution arising from the Sept. 11 attacks, ruling Thursday that the government cannot seek to execute Zacarias Moussaoui or introduce trial evidence linking the al-Qaida loyalist to the suicide hijackings.

U.S. District Judge Leonie Brinkema punished the government for refusing court orders to make three high-level al-Qaida prisoners available to Moussaoui.

She forced the Bush administration to choose between taking the dispute over witnesses to a federal appeals court or moving Moussaoui’s case from a civilian court to a military tribunal.

Prosecutors rejected the third option of presenting the government’s case without Sept. 11 testimony, even though the indictment alleges that Moussaoui was part of a much broader al-Qaida conspiracy against the United States.

“The interests of justice require that the government have the opportunity to prove the full scope of the conspiracy alleged in the indictment, which included the brutal attacks on Sept. 11, 2001,” U.S. Attorney Paul McNulty said in reaction to the ruling.

Brinkema rejected dismissing all charges, a punishment proposed by Moussaoui and his lawyers and not contested by the government — which saw dismissal as the surest way to trigger an appellate court intervention.

Brinkema expressed doubt about a military tribunal, which could include closed proceedings, saying Moussaoui should be tried in the “open and public forum” of a civilian court.

The trial of Moussaoui has been delayed by the unprecedented legal dispute over his access to al-Qaida captives, enemy combatants held abroad in secret locations.

Brinkema concluded that the defendant, a French citizen, had a constitutional right to witnesses who might exonerate him or save him from the death penalty.

The government countered that Moussaoui has no right to question al-Qaida prisoners, whose every word of trial testimony could reveal classified information and harm the war against terrorism.

Prosecutors were especially chagrined at the possibility of Moussaoui directly questioning his al-Qaida colleagues, a right he would normally have because he’s representing himself.

“We continue to believe that the Constitution does not require, and national security will not permit, the government to allow Moussaoui, an avowed terrorist, to have direct access to his terrorist confederates,” McNulty said.

Brinkema, however, said Moussaoui deserved access to witnesses who might back up his claim that he was not part of the Sept. 11 attacks.

The judge concluded “it would simply be unfair to require Moussaoui to defend against such prejudicial accusations while being denied the ability to present testimony from witnesses who could assist him in contradicting those accusations.”

Explaining elimination of the death penalty, Brinkema said: “That the United States has deprived Moussaoui of any opportunity to present critical testimony from the detainees at issue in defense of his life requires, as a sanction, the elimination of the death penalty as a possible sentence,” she said. “The defendant remains exposed to possible sentences of life imprisonment.”

Robert Precht, assistant dean for public service at the University of Michigan Law School, said he believes the government will lose an appeal to restore its Sept. 11 evidence.

He said if the appellate judges overturned the ruling, the district judge would probably impose the more severe penalty and dismiss the charges. Then, he said, the government would appeal again “and that hot potato would be tossed back” to the appeals court.

Precht, a defense lawyer in the 1993 World Trade Center bombing case, said the appellate judges would not want continuing pretrial appeals.

Brinkema, a Clinton administration nominee who was a federal prosecutor, postponed the effect of her ruling so the government could appeal.

Two of the prisoners were among Osama bin Laden’s top operatives, Sept. 11 mastermind Khalid Shaikh Mohammed and a key planner of the attacks, Ramzi Binalshibh. The third is Mustafa Ahmed al-Hawsawi, a suspected paymaster for al-Qaida.

The government could move the case to a military tribunal, where greater secrecy could be allowed, but Brinkema said she ruled out dismissing the case in order to keep the trial in “an open and public forum.”

She also cited “the unprecedented investment of both human and material resources” in a case that has been in the court for nearly two years without a trial.

Brinkema was responding to government defiance of her rulings in January and August, which granted Moussaoui the right to question the prisoners through a satellite connection. Their testimony also could have been used during his trial.

Frank Dunham Jr., one of the court-appointed lawyers representing Moussaoui’s interests while he serves as his own lawyer, issued a statement that said the government is now relieved of a major burden.

“The government has said before the dispute that access to these witnesses put it to a … choice of compromising national security or allowing an accused terrorist to go free. Today’s opinion allows the government to avoid that dilemma entirely.”

In barring the Sept. 11 evidence, Brinkema said the government could still obtain a conviction by proving that Moussaoui was part of al-Qaida conspiracy that did not involve the 2001 attacks.

The government had a much heavier burden to show that Moussaoui is eligible for the death penalty, the judge said, because prosecutors must show that his actions resulted in murder.

If Moussaoui is shown to be a minor player in al-Qaida’s war against the United States, he couldn’t lawfully “be sentenced to death for the actions of other members of al-Qaida who perpetrated the Sept. 11 attacks,” the judge said.