WASHINGTON — Is it legal for the president, acting on his own authority and without a court warrant, to order federal officials to eavesdrop on people within the United States?
President Bush gave one answer to that question Saturday, saying he was justified in ordering the National Security Agency to spy on "people with known links to Al Qaeda and related terrorist organizations."
But a Supreme Court decision more than 30 years ago raises questions about Bush's position. And several legal experts note that a special court exists that could rule on the surveillance requests.
As a result, the controversy over the program Bush approved is not likely to end quickly.
In making his case, Bush argued that the program was targeted, not an open-ended one that encompassed a group of people, such as Muslim men. Moreover, the NSA was listening to "international communications" made by possible terrorists, he said.
And the purpose of the spying was clear: "to detect and prevent terrorist attacks" by intercepting the calls of plotters, the president said.
But Bush did not explain why he chose to bypass the procedure established in a 1978 law for such operations. That measure requires the approval of a special court before conversations can be intercepted and recorded. The court may authorize warrants to obtain "foreign intelligence" information if the target is linked to "international terrorism."
Throughout his administration -- and especially since the Sept. 11, 2001, attacks -- Bush has been aggressive in asserting executive powers. And part of his explanation for approving the spying program fits this pattern.
Bush said his decision was "fully consistent with my constitutional responsibilities and authorities." And the president's lawyers have maintained that the commander in chief has the "inherent" authority to act in the interest of national security, even if he overrides the law.
But the Supreme Court did not accept that claim when it was tested in the past.
In 1972, the justices unanimously rejected President Nixon's contention that he had the power to order wiretapping without a warrant to protect national security. The decision came in the case of three men who had allegedly plotted to bomb a CIA facility in Michigan. After the ruling, charges in the case were dismissed.
The 4th Amendment protects Americans from "unreasonable searches and seizures" by the government, said then-Justice Lewis F. Powell, a Nixon appointee, delivering the court's ruling, and such freedoms "cannot be properly guaranteed if domestic security surveillances are conducted solely within the discretion of the executive branch."
He said Nixon's lawyer should have obtained a search warrant from a judge before the government tapped the telephones of the alleged plotters.
"We recognize, as we have before, the constitutional basis of the president's domestic security role, but we think it must be exercised in a manner compatible with the 4th Amendment," Powell said.
But in the decision, Powell said the court was not ruling on the "president's surveillance power with respect to the activities of foreign powers, within or without this country."
Bush on Saturday said the spying by the NSA that he authorized was reviewed thoroughly by the Justice Department and the NSA's top legal officials.
But some legal experts said Saturday that they did not understand why Bush did not rely on the 1978 Foreign Intelligence Surveillance Act, known as FISA, and seek a warrant for the spying from the special court that operates within the Justice Department.
Jeffrey H. Smith, former general counsel to the CIA, said the FISA process "should have permitted, or enabled, the president to conduct this surveillance." Smith said the court sometimes was slow to act in the past but became "much more responsive" after the Sept. 11 attacks.
One senior U.S. counterterrorism official familiar with both the intelligence and law enforcement aspects of the controversy said FISA warrants -- even under emergency conditions -- can take 24 to 48 hours to be approved.
The official, who spoke on condition of anonymity when discussing classified operations, said that not long after the Sept. 11 attacks, the administration's use of wiretaps without warrants was applauded within the counterterrorism community. But potential problems arose when it continued long after "chatter" among possible terrorists of large-scale attacks had died down.
Kenneth C. Bass III, another expert on FISA, said the administration might have thought it did not have enough evidence to obtain a warrant. Bass, a Washington lawyer who worked on intelligence matters during the Carter administration, speculated that U.S. authorities might have seized a computer or a phone that was used by an Al Qaeda operative.