Vice President Dick Cheney is reported to have been the administration's top advocate for intercepting purely domestic telephone calls and e-mails, without warrants, as part of the war on terror after the September 11 attacks.
The New York Times Sunday quotes two senior intelligence officials as saying Cheney and his legal advisor took an aggressive view of the president's ability to take security measures that raised concerns by others about civil liberties.
The officials, who asked not to be named, say lawyers within the National Security Agency did not believe U.S. law allowed the type of surveillance requested by the vice president.
The officials say it was General Michael Hayden, then the head of the NSA, who reached a compromise with the White House allowing warrantless eavesdropping if one party to a conversation was outside the United States.
That decision is expected to come under intense scrutiny later this week during General Hayden's confirmation hearings as the next director of the Central Intelligence Agency.
Some information for this report was provided by Reuters.