Sen. Rand Paul (R-Ky.) called the revelation that the National Security Agency is collecting the phone records of millions of Verizon customers “an astounding assault on the Constitution.”

The Guardian obtained a leaked top secret court order issued in April requiring the communications company to turn over records on an “ongoing, daily basis,” revealing “for the first time that under the Obama administration the communication records of millions of US citizens are being collected indiscriminately and in bulk – regardless of whether they are suspected of any wrongdoing,” wrote Glenn Greenwald.

“The National Security Agency’s seizure and surveillance of virtually all of Verizon’s phone customers is an astounding assault on the Constitution. After revelations that the Internal Revenue Service targeted political dissidents and the Department of Justice seized reporters’ phone records, it would appear that this administration has now sunk to a new low,” Sen. Rand Paul (R-Ky.) said this morning.

Paul noted that his amendment with Sen. Mike Lee (R-Utah) that would attach Fourth Amendment protections to the Foreign Intelligence Surveillance Act last year was defeated, with Senate Majority Leader Harry Reid saying that FISA was “necessary to protect us from the evil in this world.”

“The Bill of Rights was designed to protect us from evil, too, particularly that which always correlates with concentrated government power, and particularly Executive power,” Paul said. “If the president and Congress would obey the Fourth Amendment we all swore to uphold, this new shocking revelation that the government is now spying on citizens’ phone data en masse would never have happened.”

But Sen. Lindsey Graham (R-S.C.) said on Fox this morning Americans “should be concerned about terrorists trying to infiltrate our country and attack us, and trying to coordinate activities from overseas with — inside the country.”

“Under the FISA law you just can’t track people’s phone calls. You’ve got to have a reasonable belief that the people you’re monitoring in terms of monitoring conversations are one of the persons is involved in terrorism,” he said.

“So you’re trying to data mine and find out, you know these numbers that we know are in the hands of bad guys, whoever they’re calling. And then once you find a match, you can — you can monitor. But you just can’t monitor people’s phone calls.”