Ali Saleh al-Marri has been sitting in solitary confinement at a South Carolina Naval brig for four years, designated an enemy combatant by the Bush administration.
He's suspected of being an al Qaeda sleeper agent, who was preparing to launch a second-wave hit after the Sept. 11, 2001, terrorist attacks. But he has not had a trial nor been convicted of terrorism charges.
Monday, a federal appeals court issued a 2 to 1 opinion in the case, sending a strong message to the White House, saying al-Marri is being held illegally, and that President George W. Bush has overstepped his constitutional authority in authorizing the detainment.
"What the court is warning is that if you can do this to Mr. al-Marri, if you can pick up someone in Peoria, Ill., and hold them, potentially for life without charge, they can do it to you, they can do it to your mother," said al-Marri defense attorney Jonathan Hafetz.
Using piercing language throughout the opinion, the court wrote, "The president cannot eliminate constitutional protections with the stroke of a pen by proclaiming a civilian, even a criminal civilian, an enemy combatant subject to indefinite military detention.
"Put simply, the Constitution does not allow the president to order the military to seize civilians residing within the United States and detain them indefinitely without criminal process, and this is so even if he calls them 'enemy combatants,'" the opinion continued.
The opinion stated that the sanctioning of such presidential power "would have disastrous consequences for the Constitution — and the country."
"The court today told the president that his unilateral attempt to wage the war on terror goes way beyond that which the Constitution allows," said former Justice Department attorney Michael Greenberger, now a professor at the University of Maryland's law school.
"He's not only crossed the borderline, he's gone well into dangerous territory," Greenberger said.
Since Sept. 11, the Bush administration has argued the president has the authority to detain terrorists who might pose an imminent threat.
"What happened on 9-11 has led the administration to believe that there are so many people who are so dangerous that you detain first and worry about prosecution later, if ever," said George Washington University law professor Stephen Saltzburg.
"Their point of view is that, people who are conspiring with al Qaeda, who may be sleepers in the U.S., pose a danger that can't adequately be dealt with through normal criminal law proceedings," he said.
The Justice Department released a statement after the ruling, saying, "The president has made clear that he intends to use all available tools at his disposal to protect Americans from further al Qaeda attack, including the capture and detention of al Qaeda agents who enter our borders."
"I'm disappointed by the decision," said Attorney General Alberto Gonzales. He also noted that the Justice Department will "seek rehearing … before the entire circuit," the 13 active members of the 4th Circuit Court of Appeals, the court that issued Monday's opinion.
If the department loses out, it will likely appeal to the Supreme Court.
"Al-Marri was sent to the United States as a facilitator for other al Qaeda individuals who would come in to conduct follow-on attacks," then-Attorney General John Ashcroft told ABC News in an exclusive interview in June 2003.
The government arrested al-Marri in December 2001, then charged him in a criminal complaint filed in December 2002. The FBI alleged he repeatedly attempted to contact an al Qaeda leader suspected of helping to finance the 9/11 attacks.
The Justice Department also claimed in the statement it released Monday that "In the summer of 2001, he [al-Marri] met with Khalid Shaykh Muhammed, the mastermind of the Sept. 11 attacks and entered the United States just before Sept. 11 to serve as an al Qaeda sleeper agent and to explore methods of disrupting the U.S. financial system."
When FBI agents searched al-Marri's West Peoria, Ill., home after his arrest, they said they found dozens of credit card numbers on his laptop, information on toxic chemicals, and lectures from Osama bin Laden and other top al Qaeda associates. They also said they'd discovered an almanac with a variety of potential targets marked, including dams and railroads.
Al-Marri entered the U.S. legally on Sept. 10, 2001.
Though al-Marri is a citizen of Qatar, not the United States, the court said he could not be held indefinitely without the right to due process.
The court concluded that "the president claims power that far exceeds that granted him by the Constitution."
But one judge on the appeals panel did not agree with the majority opinion.
"I believe the district court correctly concluded that the president had the authority to detain al-Marri as an enemy combatant or belligerent," Judge Henry E. Hudson wrote in his dissent.
"Although al-Marri was not personally engaged in armed conflict with U.S. forces, he is the type of stealth warrior used by al Qaeda to perpetrate terrorist acts against the United States."
Though the two judges who made up the majority rebuked the standing policy, their opinion noted that al-Marri shouldn't necessarily go free, but instead, be tried by a civilian court.
"If the government accurately describes al-Marri's conduct, he has committed grave crimes. But we have found no authority for holding that the evidence offered by the government affords a basis for treating al-Marri as an enemy combatant, or as anything other than a civilian," Judge Diana Gribbon Motz wrote.
"This does not mean that al-Marri must be set free. Like others accused of terrorist activity in this country … al-Marri can be returned to civilian prosecutors, tried on criminal charges, and, if convicted, punished severely."