The details of the National Security Agency’s surveillance programs have been gradually emerging since Edward Snowden, a former contractor for the agency, leaked classified documents describing them earlier this month. Still, basic questions remain unanswered regarding the scope of the surveillance and the protocols according to which the NSA gathers and analyzes data. Google, one of the corporations cooperating with the NSA, challenged a gag order on Tuesday in the hope of being able to discuss the relationship freely:

The legal filing, which invokes the First Amendment’s guarantee of free speech, is the latest move by the California-based tech giant to protect its reputation in the aftermath of news reports about broad National Security Agency surveillance of Internet traffic. . .

A high-profile legal showdown might help Google’s efforts to portray itself as aggressively resisting government surveillance, and a victory could bolster the company’s campaign to portray government surveillance requests as targeted narrowly and affecting only a small number of users. . .

In its petition, Google sought permission to publish information about how many government data requests the surveillance court approves and how many user accounts are affected. Google long has made regular reports with regard to other data demands from the U.S. government and other governments worldwide, but it has been forced to exclude requests from the surveillance court, which oversees an array of official monitoring efforts that target foreigners.

Facebook, Microsoft and Yahoo in recent days have won federal government permission to include requests from the court as part of the overall number of data requests they receive from federal, state and local officials. Google has rejected that approach as too imprecise to help users understand the scope of its cooperation with federal surveillance.

“Google’s users are concerned about the allegations. Google must respond to such claims with more than generalities,” it said.

Craig Timberg and Cecilia Kang

Speaking Tuesday before a House committee, intelligence officials defended the surveillance, claiming that data collected by the NSA have helped law enforcement to foil dozens of terrorist plots:

Gen. Keith B. Alexander, the head of the NSA, told the committee that the programs had helped prevent “potential terrorist events over 50 times since 9/11.” He said at least 10 of the disrupted plots involved terrorism suspects or targets in the United States.

Alexander said officials do not plan to release additional information publicly, to avoid revealing sources and methods of operation, but he said the House and Senate intelligence committees will receive classified details of the thwarted plots. . .

Alexander said that more than 90 percent of the information on the foiled plots came from a program targeting the communications of foreigners, known as PRISM. The program was authorized under Section 702 of a 2008 law that amended the Foreign Intelligence Surveillance Act (FISA). . .

Under Section 702, the NSA must destroy any data collected about U.S. persons — citizens or lawful permanent residents — that have nothing to do with foreign intelligence, a crime or terrorism, officials said. The agency may keep the data for five years and then must purge it.

Phone data are stored in a separate repository at the NSA that can be accessed by only 22 specially trained people, officials said.

A query can be made only if the analyst has “reasonable, articulable suspicion” that the phone number to be searched is associated with a specific terrorist organization, they said.

Both programs are subject to reporting requirements, though the reports are not public.

Ellen Nakashima

One scheme that the NSA helped to frustrate involved a plan to bomb the New York City subway. A case in England led investigators to a Yahoo account belonging to a Pakistani terrorist:

In November 2008, Abid Naseer, a Pakistani student living in Manchester, England, began to e-mail a Yahoo account that was ultimately traced back to his home country. The young man’s e-mails appeared to be about young women — Nadia, Huma, Gulnaz and Fozia — and which of them would make a “faithful and loving wife.”

British investigators later determined that the four names were code for different types of explosives and that a final April 2009 e-mail announcing a “marriage to Nadia” between the 15th and the 20th was a signal that a terrorist attack in England was imminent, according to British court documents.

It is unclear exactly how British intelligence services linked the Pakistani e-mail address,, to a senior al-Qaeda operative who communicated in a kind of pigeon code to his distant allies. But the intelligence helped stop the plot in England, and the address somehow made its way to the National Security Agency at Fort Meade, Md.

A few months later, the NSA was monitoring the Yahoo user in Pakistan when a peculiar message arrived from a man named Najibullah Zazi, an Afghan American living in Aurora, Colo. He asked about “mixing of [flavor and ghee oil] and I do not know the amount, plz right away.”

A short time later, on Sept. 9, 2009, a second message arrived that echoed the code used in the British plot: “The marriage is ready,” Zazi wrote. . .

In the end, the e-mails and additional surveillance foiled a plot by Zazi and two others to conduct suicide bombings in the New York City subway system just days after he sent the “marriage is ready” e-mail. . .

Some critics of NSA surveillance suggested that the collection of data under a program called PRISM was not essential to Zazi’s capture because the British first obtained the critical e-mail address.

Still, the case study provides a rare glimpse of how the broad surveillance practices of the United States, often in concert with allies, are deployed.

Peter Finn and Greg Miller

Timothy Lee argues that by so carefully keeping its operations secret, the NSA has harmed its reputation and, by extension, national security:

In his testimony, NSA Director Keith Alexander suggested that the existence of the surveillance program itself had been put in jeopardy by Ed Snowden’s leaks. He described the NSA’s FISA spying powers as “the best counterterrorism tools that we have to go after these guys. We can’t lose those capabilities.”

That’s puzzling because the NSA has exactly the same surveillance capabilities it had two weeks ago. What Snowden’s disclosures clearly did do, however, was to produce a lot of negative media coverage. Alexander is worried that public disclosure will lead to a public backlash that will cause Congress to revise the laws that authorized the programs in the first place. But if that’s his concern, Alexander’s battle is not with terrorism, but with democracy.

Indeed, the NSA’s excessive secrecy arguably endangered its own programs. If the agency had been more transparent about how its surveillance programs worked, it might have persuaded the public that there were adequate safeguards in place, building broad public support for the programs.

Instead, by acting like it had something to hide, the NSA has caused many Americans to assume the worst. For example, 38 percent of Americans believe the NSA can listen to their phone calls without a warrant, despite the agency’s claims to the contrary. By keeping the American people in the dark, they ensured only that if and when the program was exposed, it would cast the NSA in the worst possible light.

Timothy Lee

While most Americans support the NSA’s surveillance programs, majorities also want public hearings in Congress on the matter, regardless of political affiliation. For past coverage of the NSA, continue reading here.