WASHINGTON -- Legal specialists yesterday questioned the accuracy of President Bush's sweeping contentions about the legality of his domestic spying program, particularly his assertion in his State of the Union speech on Tuesday that ''previous presidents have used the same constitutional authority I have."
Shortly after the terrorist attacks of Sept. 11, 2001, Bush authorized the National Security Agency to intercept overseas calls from the United States without first seeking a warrant, asserting he had the right to do so under his wartime powers. On Tuesday night, he defended his program by saying past presidents have exerted the same powers.
But legal specialists said yesterday that wiretaps ordered by previous presidents were put in place before warrants were required for investigations involving national security. Since Congress passed the law requiring warrants in 1978, no president but Bush has defied it, specialists said.
Bush's contention that past presidents did the same thing as he has done ''is either intentionally misleading or downright false," said David Cole, a Georgetown University law professor. Only Bush has made the assertion that his wartime powers should supersede an act of Congress, Cole said.
Bush repeated his assertions about the legality of his spying program at a speech yesterday in Nashville. The president has been seeking to build public support for the program in advance of Senate hearings into the matter next week.
But Bush's comments in the State of the Union, which highlighted a week of election-style campaigning to defend the program, were almost entirely disputed yesterday by legal specialists across the ideological spectrum.
For example, Bush strongly implied that if his program had been in place before the terrorist attacks, the government would have identified two of the hijackers who were placing international calls from inside the United States.
But the 9/11 Commission found that the government had already grown suspicious about both of the hijackers in question before the attacks took place. Bureaucratic failures to share information about the hijackers, not ignorance of their existence, was the problem, the commission said.
Moreover, Bush said in his address that ''appropriate members of Congress have been kept informed" about the program. But Senator Arlen Specter, a Pennsylvania Republican and chairman of the Judiciary Committee, has said that under law Bush was required to brief all members of the intelligence committees -- not just their leaders, as he did.
Bush's assertion that his program was legal prompted a group of 14 prominent law professors, including both liberals and conservatives, to pen a joint letter objecting to his arguments. An expanded version of their letter rebutting Bush's assertions will be released today, the professors said.
Richard Epstein, a University of Chicago law professor and a member of the group, said he believes the Supreme Court would reject Bush's assertions that his wartime powers authorized him to override the law.
''I find every bit of this legal argument disingenuous," Epstein said. ''The president's position is essentially that [Congress] is not doing the right thing, so I'm going to act on my own."
The White House referred all questions about the spying section of Bush's speech to the Justice Department, where spokeswoman Tasia Scolinos acknowledged yesterday that all of the surveillance programs approved by past presidents pre-dated the warrant requirement.
But, she said, no court has said the 1978 the law changes the president's inherent constitutional power to conduct surveillance for national security purposes. And she said a 2002 opinion by a secret federal court acknowledged that the president had sweeping surveillance powers.
But Cole, the Georgetown professor, said the Bush administration is misstating the ruling in the 2002 case, including its requirement that the Justice Department seek warrants in national security cases. Cole said the case supported the notion that Congress could regulate the president's use of his surveillance powers.
Scolinos said Attorney General Alberto Gonzales, who is scheduled to testify before the Senate Judiciary Committee about the program on Monday, would offer a more detailed defense of the administration's legal theories.
Yesterday, some of Bush's defenders pointed out on conservative websites that the Clinton administration had authorized a search of the home of Aldrich Ames, a suspected Soviet spy, without a warrant in 1993.
But legal specialists said the Ames case is irrelevant because it involved a physical search of Ames's home, and the 1978 law did not require warrants for physical searches. The year after the Ames search, 1994, the law was amended to require warrants for physical searches and wiretaps.
Philip Heymann, a Harvard law professor who was then the deputy US attorney general and helped oversee the Ames investigation, said the Clinton administration began seeking warrants for physical searches as soon as the new law went into effect.
''The bottom line is, I know of no electronic surveillance for intelligence purposes since [the 1978 warrant law] was passed that was not done under the . . . statute," Heymann said.