WASHINGTON -- The Supreme Court's ruling in the Guantanamo Bay case is a setback to President Bush's aggressive pursuit of broad wartime powers, a trademark of his presidency, legal analysts and historians said yesterday.
Since the Sept. 11 attacks, Bush has asserted expansive and virtually unconstrained presidential authority in advancing his national security and counterterrorism policies.
The latest court ruling, which rejected his bid to use military tribunals for terrorism suspects, challenged the administration's theory and amounted to a rare reining-in of a president who recently dubbed himself the "Decider."
It follows other challenges to Bush's authority, including by members of his own party, who have been showing increasingly resistance to the president's assertions of executive power. Just this week, Congress debated Bush's frequent use of so-called "signing statements" to challenge provisions of laws sent to him for his signature.
"It casts a cloud over all of these legal precedents that President Bush is advancing to justify executive omnipotence," said Bruce Fein, a Reagan administration White House counsel who has been a vocal critic of the Bush team's assertions.
"The court is saying President Bush has just gone too far - he's sneered at courts, he's sneered at the Congress. This was finally pulling in the reins and saying, `No, you don't have unchecked powers.'"
Bush and his aides tried to play down the significance of the ruling, rejecting the notion that it would tie Bush's hands and sidestepping questions about its implications beyond Guantanamo.
The president, who got word of the ruling during meetings with Japanese Prime Minister Junichiro Koizumi, declined to discuss its implications for his anti-terror policies at a news conference a short time later. He said he would work with Congress to find a way to try the detainees.
The ruling "is what it is. ... It's something you deal with," said Tony Snow, the White House press secretary, adding that administration lawyers were weighing options for dealing with the detainees.
"There's not seen any sort of implicit curtailment of [Bush's] ability to fight the war on terror," Snow said.
He also contended that the ruling did not have broader ramifications for other Bush policies, such as his ability to continue the National Security Agency's warrantless surveillance program. Linking the issues is "talking apples and oranges," Snow said.
Legal scholars and analysts, however, called the ruling a sharp rebuke to Bush because it undercuts his push - detailed most vocally by Vice President Dick Cheney - to expand presidential power, particularly on security matters. That effort has at its root the theory that, because the Constitution makes the president the commander-in-chief, he has untrammeled authority to act on national security matters in wartime.
It was articulated succinctly by Cheney, who said last year that "the president of the United States needs to have his constitutional powers unimpaired, if you will, in terms of the conduct of national security policy." The White House reminded reporters of the comments yesterday.
"They really tried to make this far-reaching argument that the president can set up tribunals as part of his inherent powers," said Timothy E. Lynch, an analyst at the libertarian Cato Institute. "This is a fairly strong repudiation of that.
Democrats cheered the ruling as a badly needed check on Bush's authority.
Vermont Sen. Patrick J. Leahy, the senior Democrat on the Judiciary Committee, said the Bush administration's assertions of executive power, rather than a legitimate exercise of constitutional prerogatives, were part of a record that "has violated fundamental American values, tarnished our standing in the world and hindered the partnerships we need with our allies."
"This arrogance and incompetence have delayed and weakened the handling of the war on terror, not because of any coherent strategic view it had, but because of its stubborn unilateralism and dangerous theory of unfettered power," Leahy said in a statement.
Senators said they would move swiftly to draft a measure to deal with detainee trials, some of them agreeing with the court that Bush overstepped in trying to establish tribunals himself.
Republican Sen. Arlen Specter of Pennsylvania, the Judiciary chairman, said the court's decision made it "obvious" that "there is no inherent authority." That conclusion might also be relevant as Congress considers the legality of the NSA's warrantless surveillance program, he said.
Yesterday's ruling was the second time the court had rejected Bush's arguments about the scope of his authority. In 2004, the court rejected the administration's argument that so-called enemy combatants - people seized in the course of the war on terror - had no right to challenge their detentions in U.S. courts.
"Anybody in the White House who thinks that they can just assert that we're in war, the president is commander-in-chief, so he can do just about whatever he wants, they should know by now that that argument is not going to get them very far in this court. They'd better come up with another theory," Cato's Lynch said.
The latest ruling also drew comparisons to the court's rejection in 1952 of President Harry S. Truman's authority to seize steel mills during the Korean War.
"It is a real slap at the president," said Princeton historian Fred I. Greenstein, who said Bush has been "very Truman-like" in his impulse to claim broad executive powers.