An Associated Press-Ipsos poll conducted in February found Americans evenly split on whether it was appropriate for the administration to listen to Americans' phone calls without obtaining a court warrant. Several people interviewed by the AP on Thursday had been questioned in that poll.

There was no polling yet on the new NSA revelations, but anecdotal evidence suggested the issue was destined to cause the kind of passionate split the nation has grown familiar with since the 2000 election.

Left- and right-wing political blogs seized on the report, many of them adding their own sarcasm ¡ª "NSA accused of protecting U.S. from terrorists," offered conservative site Power Line.

Meanwhile, a poster on the liberal site Daily Kos lamented, "So much for privacy ¡ª telecoms cave to government." It suggested readers complain to the companies working with NSA ¡ª AT&T Corp., Verizon Communications Inc. and BellSouth Corp.

And at left-wing Firedoglake, a poster suggested the program violated the very notions of liberty and freedom. Above the posting was a picture of a farm of satellite dishes and the headline, "Are they listening?"

Some bloggers tore into USA Today for publishing the information in the first place, even suggesting it had helped make Qwest Communications International Inc. the terrorists' carrier of choice because it refused to turn over records to the NSA.

Bush emphasized leaks of sensitive intelligence hurt "our ability to defeat this enemy."

"I think they should find the leakers and prosecute them," said Gayle Dethman, a florist who works from home in Portland, Ore. "I want to be protected, and I think they need to do what they have to do."

The NSA discussion appeared to be the next chapter in the nation's sorting-out of the liberty-security balance, and how much power should be entrusted to the administration in the name of preventing another Sept. 11.

For James Roberts, a 72-year-old retiree and Navy veteran living in Seneca, S.C., Bush has gone too far. He said he worries about a drift toward a "police state" and an administration unconcerned with accountability.

"It is any business of the government if I call my sister-in-law in Chicago and say, `How you doing?'" he asked. "I think it is truly an invasion of privacy. It's a violation of individual rights."