''I think the American people expect the United States government and the president to do what they can to make sure there's not an attack by foreign terrorists,'' Bush said just before landing here to begin a four-day stay in West Africa.
President Bush is concerned that media disclosure of the program will cripple work to foil terrorists, she said. ''I think he was worried that it would undermine our efforts by alerting terrorists to what our efforts are,'' Bush said.
Bush's secret order gave the National Security Agency permission to listen in on international phone calls and peek at e-mails between Americans and suspected terrorists.
Administration officials claim a congressional resolution passed after the attacks of Sept. 11, 2001 - a resolution that authorized him to use force in the fight against terrorism - gave the president the authority to order the program.
''I thought they were wrong,'' Sen. Arlen Specter, R-Pa., said on ABC's ''This Week.''
Specter is one of several Republicans and Democrats who are questioning the administration's authority to engage in domestic spying without court warrants. Attorney General Alberto Gonzales has agreed to testify at hearings next month before the Judiciary Committee, which Specter chairs.
Specter also said that although the question of impeachment had not yet arisen for him, he would pursue it if he believes Bush broke the law.
''Impeachment is a remedy,'' he said. ''After impeachment, you could have a criminal prosecution, but the principal remedy . . . under our society is to pay a political price.''
Committee members, including GOP Sen. Sam Brownback of Kansas, have expressed doubt about Bush's legal argument for the program.
''We're not going to give him a blank check, and just because we're of the same party doesn't mean we're not going to look at this very closely,'' Specter said. ''And I moved immediately when the matter was disclosed to say that I would use my authority as chairman of the Judiciary Committee to have hearings, and we're going to pursue it.''
