But the court also said the president still has the option of going to Congress now to seek that authorization.
Asked about the decision shortly after the ruling was handed down, Bush said he needed time to study it, but said his administration will abide by the decision. "To the extent that the Congress is given any latitude to develop a way forward using military tribunals, we will work with them," he added.
Case Demanded Public Trial
The case involves Salim Ahmed Hamdan, one of about 450 prisoners being held at Guantanamo Bay. Hamdan, a native of Yemen, has been held for four years at the detention facility.
In his lawsuit, "Hamdan vs. [Secretary of Defense Donald] Rumsfeld," the Yemeni challenged the Bush administration's plan to try him before a secret military commission.
Hamdan worked as a driver and guard for Osama bin Laden, the founder of Al-Qaeda, which the U.S. government blames for the attacks in the United States on September 11, 2001.
Three of the court's justices disagreed with the majority opinion. One, Justice Clarence Thomas, complained that the decision would "sorely hamper the president's ability to confront and defeat a new and deadly enemy."
Many world leaders, including U.S. allies, have urged Bush to shut down the Guantanamo detention center. Critics say the facility violates Geneva Convention rules on the treatment of prisoners. Only this month, three prisoners there committed suicide.
Blow For Administration?
White House spokesman Tony Snow was asked about the ruling repeatedly during the June 29 press briefing. He, too, said it needed further study, but he dismissed the idea that the court had repudiated the administration's strategy.
Snow characterized the court's decision as a difference of opinion over how the White House chose to organize the courts, saying that the "Supreme Court has said that it disagrees with the way in which the commissions were convened and has laid down some guidelines for proceeding."
That interpretation couldn't be further from the truth, according to Robert Spitzer, a professor of political science and U.S. constitutional history at the State University of New York at Cortland. He says the ruling is a strong reassertion of two important U.S. constitutional doctrines: the separation of powers, and checks and balances.
Under the separation-of-power doctrine, the executive, legislative, and judicial branches of government may not infringe on one another's constitutional authority. Under the checks and balances provision, each branch of government has the authority to ensure that another branch doesn't violate the separation of powers.
All three branches of government are involved in the current ruling: The Supreme Court told the White House that it cannot set up the military commissions without the authorization of Congress.
Spitzer said in its decision, the court said Bush can still ask Congress for that authorization. The only option the decision ruled out was unilateral action, he says.
"This is a president who has claimed very, very great executive powers, far greater than any of his predecessors, not only with respect to war-related activities, but other activities, too," Spitzer says. "And once again the court has said that the president does owe an obligation to the separation of powers and checks and balances. And that includes not only the right of the courts to review actions but also the responsibility of Congress to legislate when law is required. So those principles, I think, were emphatically upheld by the court today."
Congressional Support May Be Lacking
What's next? While Bush says he plans to see what kind of permission he can arrange with Congress, it's not certain legislators will give him all the authority he wants. The Republican Party may control both the House and Senate, but many legislators, even some Republicans, have expressed impatience with his style of governing.
As for the Guantanamo prisoners themselves, Spitzer says Bush has a range of options. "The president could certainly funnel these cases through the federal courts or through a constituted court-martial court. Those procedures were specifically mentioned by the Supreme Court ruling," he says.
"Ultimately, one assumes that the president could and would go to Congress," Spitzer adds. "But the president could take action immediately, if he wants to, to process the detainees at Guantanamo, as long as he follows the procedures that the court set down in its decision."
Whatever Bush does, Spitzer says, he knows he'll have to make sure he doesn't run afoul of the Supreme Court again.