Ali Al-Marri, the only person being held by the military as an enemy combatant on U.S. soil, says the president "has no inherent authority" to detain him indefinitely.

In legal papers filed with the Supreme Court Wednesday, Al-Marri said he believes the U.S. Court of Appeals for the 4th Circuit erred in its 5-4 ruling last year that declared that the president could keep him locked up for years without trial.

Al-Marri's case against the government is expected later this year. But what remains unclear is what position the new administration will take in the case that is seen as major test of presidential authority and civil liberties.

Al-Marri's lawyers wrote in the brief that the court's ruling "must be reversed."

"That ruling transgresses black-letter principles of statutory construction, flouts Congresss intent, and raises grave constitutional questions unnecessarily. It deviates dangerously from this Nations most cherished constitutional principles and traditions," Al-Marri's lawyers wrote. 

Al-Marri was arrested in Peoria, IL a couple of months after the September 11th attacks and is accused of being an al Qaeda operative sent to the United States on September 10, 2001 to take part in another attack. 

In 2003, President Bush signed an executive order labeling Al-Marri an "enemy combatant" and removing him from civilian custody. The order made the Defense Department responsible for Al-Marri who has been kept in isolation at the Navy brig in Charleston, SC.

The Supreme Court granted the case knowing it would be argued by the new administration. What is not known is what position the Obama administration will take. The current schedule mandates a response by February 20. 

Last month, a spokesperson to then President-elect Obama told the Associated Press, "We are not going to comment on cases pending before our courts. President-elect Obama has repeatedly said that he believes that our current legal framework has failed to successfully and swiftly prosecute terrorists. He will make decisions about how to handle detainees as president when his national security and legal teams are in place."

Congressional approval for Obama's selection for Solicitor General, Harvard Law School dean Elena Kagan, is still pending. Kagans input would presumably play an important role in the final decision in how to handle the case. She may even be called upon to argue it in front of the Supreme Court. It is possible the administration will ask the court for more time to file its response.