Washington - The Supreme Court agreed on Friday to decide whether an al Qaeda suspect can be indefinitely imprisoned in the United States without charges, a test of President George W. Bush's war-on-terrorism powers.

    The nation's highest court said it would hear an appeal by a Qatari national, Ali al-Marri, the only person now being held in the United States as an "enemy combatant," arguing that Bush exceeded his powers and disregarded fundamental American legal principles.

    While President-elect Barack Obama has strongly opposed Bush's policies and has vowed to close the U.S. military prison at Guantanamo Bay in Cuba, he and his aides have not said what position they will take in Marri's case.

    Since Bush designated Marri an enemy combatant in June 2003, he has been held in solitary confinement in a U.S. Navy brig in Charleston, South Carolina, without being charged.

    Marri's attorneys appealed a U.S. appeals court's ruling in July that Congress gave Bush the power to detain him as part of its authorization for use of military force after the September 11, 2001, attacks by al Qaeda.

    They said the law authorizing military force and the U.S. Constitution do not allow for the indefinite military detention of a person lawfully residing in the United States, without criminal charges or a trial.

    Jonathan Hafetz, an attorney with the American Civil Liberties Union who represents Marri, said he was pleased the Supreme Court accepted the case for review.

    "Because the President Says So"

    Steven Shapiro, the group's legal director, said, "We are hopeful that the court will ... ensure that people in this country cannot be seized from their homes and imprisoned indefinitely simply because the president says so."

    The Supreme Court's decision to review the case will force the incoming Obama administration to quickly focus on U.S. detention policy, said Sharon Bradford Franklin, senior counsel at a group called the Constitution Project.

    She said she hoped that Obama will reject the Bush administration's position that the United States may hold a civilian in military detention indefinitely and will charge or release Marri.

    The Supreme Court in June rebuked Bush in a landmark ruling that prisoners held at the U.S. military base at Guantanamo can go before federal judges in Washington to seek their release. There are now about 250 prisoners at Guantanamo.

    It also ruled against the Bush administration in three other war-on-terrorism cases in 2006 and 2004.

    The Supreme Court will hear arguments in Marri's case in March, with a decision expected by the end of June. The case could be the most important of the court's current term.

    Marri entered the United States on September 10, 2001, and was said by a captured al Qaeda member to have come to help operatives plotting a second wave of attacks.

    A legal U.S. resident, Marri was initially detained in December 2001 in the investigation of the September 11 attacks.

    He was later indicted in Illinois, where he had attended school, for credit card fraud, making false statements to the FBI and other charges. Marri pleaded not guilty.

    The U.S. government dropped the criminal charges in June 2003, when Bush designated Marri an enemy combatant and he was taken to the brig in Charleston.

    Only two others have been held as enemy combatants inside the United States since the September 11 attacks.

    In January 2006, Jose Padilla, held for three years at the same brig in Charleston, had his case transferred to a criminal court in Miami, where he was later convicted on charges of offering his services to terrorists.

    Yaser Esam Hamdi, another U.S. citizen held at the brig for two years, was deported to Saudi Arabia after the Supreme Court in 2004 upheld his right to challenge his detention.

    Bush administration lawyers unsuccessfully urged the Supreme Court to reject Marri's appeal, without hearing the case.

    They said Bush has the power to order Marri's detention, and that the case should be allowed to go back to a federal judge in South Carolina to give Marri another opportunity to challenge his designation as an enemy combatant.

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    (Editing by Kristin Roberts and Jackie Frank.)