In the weeks after the Sept. 11 attacks, Vice President Dick Cheney and his top legal adviser argued that the National Security Agency should intercept purely domestic telephone calls and e-mail messages without warrants in the hunt for terrorists, according to two senior intelligence officials.

But N.S.A. lawyers, trained in the agency’s strict rules against domestic spying and reluctant to approve any eavesdropping without warrants, insisted that it should be limited to communications into and out of the country, said the officials, who were granted anonymity to discuss the debate inside the Bush administration late in 2001.

The N.S.A.’s position ultimately prevailed. But just how Gen. Michael V. Hayden, the director of the agency at the time, designed the program, persuaded wary N.S.A. officers to accept it and sold the White House on its limits is not yet clear. ~The New York Times