We learned yesterday that the National Security Agency (NSA) obtained a top-secret court order that forces Verizon to hand telephone records of millions of US customers over to the government. Today, the Obama administration is defending the practice as a critical tool for preventing terrorist attacks.

The Guardian, which uncovered and published the secret court order, today detailed the White House's response. The Guardian wrote:

The White House has sought to justify its surveillance of millions of Americans' phone records as anger grows over revelations that a secret court order gives the National Security Agency blanket authority to collect call data from a major phone carrier. Politicians and civil liberties campaigners described the disclosures, revealed by the Guardian on Wednesday, as the most sweeping intrusion into private data they had ever seen by the US government. But the Obama administration, while declining to comment on the specific order, said the practice was "a critical tool in protecting the nation from terrorist threats to the United States."

The phone record collection doesn't target only suspected terrorists. The court order issued by the Foreign Intelligence Surveillance Court forces Verizon to give the NSA "all call detail records or 'telephony' metadata created by Verizon for communications (i) between the United States and abroad; or (ii) wholly within the United States, including local telephone calls." The order, which covers a three-month period ending July 19, means the government is receiving data such as "phone numbers of both parties, the duration of the conversation, the time of the conversation, location data, telephone calling card numbers, and unique identifiers pertaining to the phones," as we noted yesterday.

Such call detail collection also occurred during the Bush administration. US officials say it is allowed under the Patriot Act passed in 2001.

An unnamed Obama administration official quoted by the Associated Press said that "[o]n its face, the order reprinted in the article does not allow the government to listen in on anyone's telephone calls." Call metadata can help the government identify the people making the phone calls, however.

"It allows counter-terrorism personnel to discover whether known or suspected terrorists have been in contact with other persons who may be engaged in terrorist activities, particularly people located inside the United States," the administration official quoted by The Guardian said.

UPDATE: Senate Intelligence Committee leadership said the phone records collection has been occurring since 2007. “Everyone’s been aware of it for years, every member of the Senate,” said Sen. Saxby Chambliss (R-GA), according to The Hill. Verizon has also published a response to The Guardian story. While Verizon did not comment on the accuracy of the story—unsurprising given that the court order itself forbids Verizon from revealing its contents—Verizon did say that "If Verizon were to receive such an order, we would be required to comply."