President Bush is defending his authorization of a domestic spying program designed to monitor communications with suspected terrorists in other countries. Critics of the administration say the surveillance exceeds the president's constitutional powers.
In the fight against terrorism, President Bush says the American people expect him to protect both their lives and their civil liberties.
"The terrorists will do everything they can to strike us, and I am going to continue to do everything I can within my legal authority to stop them," said Mr. Bush.
The president spoke during a visit to the National Security Agency in advance of Congressional hearings into whether he exceeded his legal powers by authorizing the N.S.A. to eavesdrop on international telephone conversations between suspected terrorists overseas and someone in the United States.
Following the September 2001 terrorist attacks in New York and Washington, Mr. Bush says he authorized the surveillance of such calls without court warrants, because part of the terrorist strategy is to place operatives inside the United States.
"They blend in with the civilian population," he said. "They get their orders from overseas, and then they emerge to strike from within. We must be able to quickly detect when someone linked to al-Qaida is communicating with someone inside of America. It's one of the challenges of protecting the American people and it's one of the lessons of September the 11th."
Mr. Bush says intelligence officials believe that had the surveillance been in place before September 11, some of those hijackers would have been detected.
The president's visit to the headquarters of the top-secret NSA is part of the Bush Administration campaign to defend the surveillance program ahead of Congressional hearings scheduled to begin February 6.
Critics from the opposition Democratic Party and some from Mr. Bush's own Republican Party say the president went around 1978 rules that would have authorized the surveillance as an emergency security measure so long as the administration got permission from a secret court within 72 hours. They say the government's eavesdropping program is illegal and violates the civil liberties of U.S. citizens.
White House Spokesman Scott McClellan says those rules were drawn-up in a different time in response to slower developing threats. This surveillance, he says, is an early warning system against imminent attack.
Mr. Bush says federal courts have consistently ruled that presidents have the Constitutional authority to conduct foreign intelligence surveillance against America's enemies.
Rejecting suggestions that the eavesdropping threatens U.S. civil liberties, the president says it is making Americans safer.
"This information has helped prevent attack and save American lives," he added. "This terrorist surveillance program includes multiple safeguards to protect civil liberties and it is fully consistent with our nation's laws and Constitution."
The Bush Administration is not shying away from the fight over the NSA surveillance. Instead, White House officials are using the issue to remind Americans of the threat and portray opponents as weak in the fight against terrorism by holding on to what senior political advisor Karl Rove calls a pre-September 11 view of national security.