Secretary of State Condoleezza Rice on Sunday defended President Bush's decision to secretly authorize the National Security Agency to eavesdrop on Americans without seeking warrants, saying the program was carefully controlled and necessary to close gaps in the nation's counterterrorism efforts.
In Sunday talk show appearances, Ms. Rice said the program was intended to eliminate the "seam" between American intelligence operations overseas and law enforcement agencies at home.
"One of the most compelling outcomes of the 9/11 commission was that a seam had developed," Ms. Rice said on "Meet the Press" on NBC. "Our intelligence agencies looked out; our law enforcement agencies looked in. And people could - terrorists could - exploit the seam between them."
"So the president is determined that he will have the ability to make certain that that seam is not there, that the communications between people, a limited number of people with Al Qaeda links here and conversations with terrorist activities outside, will be understood so that we can detect and thereby prevent terrorist attacks," she said.
Ms. Rice also said Mr. Bush decided to skirt the normal process of obtaining court-approved search warrants for the surveillance because it was too cumbersome for fast-paced counterterrorism investigations, an assertion that some national security experts, members of Congress and civil liberties advocates have challenged.
Under the Foreign Intelligence Surveillance Act of 1978, or FISA, the Federal Bureau of Investigation and the National Security Agency must obtain search warrants from a special court before conducting electronic surveillance of people suspected to be terrorists or spies. Ms. Rice said the administration believed that it needed greater agility in investigating terrorism suspects than was possible through that process.
"These are stateless networks of people who communicate, and communicate in much more fluid ways," she said. But several national security law experts and civil liberties advocates note that government officials are able to get an emergency warrant from the secret court within hours, sometimes minutes, if they can show an imminent threat.
Under "extraordinary" circumstances, the government also can wait 72 hours after beginning wiretaps to get a warrant, but the administration did not seek to do that under the special program, which monitors the international communications of some people inside the United States.
The USA Patriot Act made it easier for the government to get warrants from the court for wiretaps and physical searches, changing the standards in some critical areas.
But the law is specific in banning any searches without warrants on Americans except in extraordinary circumstances, like within 15 days of a formal declaration of war, said David D. Cole, a Georgetown University law professor who specializes in national security law.
The Bush administration has not cited any of those exemptions for the domestic eavesdropping program. The White House and other defenders of the program maintain that the president has the authority to allow such searches in the interests of national security.
"If the president thinks the process under FISA was insufficient in the wake of 9/11, the appropriate response would have been to go to Congress and expand it, not to blatantly violate the law," Mr. Cole said in an interview.
Anthony D. Romero, executive director of the American Civil Liberties Union, questioned whether the administration was criticizing the warrant system because cases in which the National Security Agency focused on Americans would not have met the standard of proof for intelligence warrants, which requires that the surveillance target be linked to a foreign terrorist group.
"It's insufficient to simply take at face value the president's claim that these people under surveillance by the N.S.A. had known links to terrorism," Mr. Romero said in an interview. "This entire program makes a mockery of our system of checks and balances."
In talk show appearances on Sunday, one Democratic lawmaker disagreed with Ms. Rice's assertions that the special court process was too cumbersome, and argued that the White House appeared to be acting in ways that conflicted with long-established laws and regulations. Senator Russell D. Feingold, Democrat of Wisconsin, said the administration was "playing fast and loose with the law in the area of national security."
Senator Arlen Specter, the Pennsylvania Republican who is chairman of the Senate Judiciary Committee, said he was not certain whether the eavesdropping program was legal. He said he expected to hold hearings on it early next year.
On CNN on Sunday, Mr. Specter struck a cautious tone. "Let's not jump to too many conclusions," he said. "Let's look at it analytically. Let's have oversight hearings, and let's find out exactly what went on."
"Whether it was legal, I think, is a matter that has to be examined," Mr. Specter said. "When you deal with issues as to legality, what advice the president got from the attorney general and others in the Department of Justice, that's a matter within the traditional purview of the Judiciary Committee."
Vice President Dick Cheney defended the program on Sunday as necessary and legal.
"It is consistent with the president's constitutional authority as commander in chief," he said in an interview that will be broadcast Monday night on the ABC program "Nightline."
"It's consistent with the resolution that was passed by the Congress after 9/11," Mr. Cheney said, referring to the resolution authorizing the president to wage the war on terror. "And it has been reviewed repeatedly by the Justice Department every single time it's been renewed, to make certain that it is, in fact, managed in a manner that's fully consistent with the Constitution and with our statutes."
Mr. Cheney said the program had "been briefed to the Congress over a dozen times," referring to briefings given to Congressional leaders.
"It's the kind of capability if we'd had before 9/11 might have led us to be able to prevent 9/11," he said.