A US military judge has ruled that the trial for Osama bin Laden's former driver should be delayed by seven weeks.
A supreme court ruling on the right of detainees to challenge their imprisonment in civil courts is expected during this period.
Salim Ahmed Hamdan will be the first person to face trial at the US naval base in Cuba.
Lawyers for Hamdan, whose trial was scheduled to start on June 2, had requested a postponement.
Keith Allred, navy captain, decided to delay the trial till it was clear whether or not the supreme court's highly anticipated ruling, expected by June 30, would affect his arraignment.
The development is the latest in a series of delays for the US government as it tries to prosecute Hamdan, a Yemeni, who acted as bin Laden's personal driver in Afghanistan, and according to evidence "helped him to evade US retribution folliwng the September 11 attacks".
There are no plans to postpone the trial of the alleged mastermind of the September 11 attacks, Khalid Sheikh Mohammed, and four others involved in the planning, because of the Hamdan case ruling, a Pentagon spokesman said on Friday.
'Potential embarrassment'
Allred, in his ruling, said: "A delay, also avoids the potential embarrassment, waste of resources and prejudice to the accused, if the supreme court ruling forces a halt to the proceedings mid-trial.
"The accused has been in confinement for six years, and another month's wait will not prejudice any party to the case.
Andrea Prasow, defence lawyer, said: "We specifically sought the continuance and are very pleased that the judge agrees that all parties will benefit from the Supreme Court's guidance regarding the applicability of the Constitution to detainees held at Guantanamo."
The supreme court is considering to a provision of the Military Commissions Act of 2006 that denies about 270 Guantanamo detainees the right to file petition of habeas corpus, a principle, that allows courts to determine whether a prisoner is being held illegally.
The pending case before the supreme court is the third time it has examined the rights of the Guantanamo detainees.