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From NPR News this is ALL THINGS CONSIDERED. I'm Melissa Block.
ROBERT SIEGEL, HOST:
And I'm Robert Siegel. General Keith Alexander, the head of the National Security Agency, returned to Capitol Hill today for the third time in a week. This time, he testified before the House Intelligence Committee about the two surveillance programs that were recently disclosed. General Alexander was joined by other members of the intelligence community and the FBI. They laid out several cases in which they said NSA surveillance helped to prevent terrorist attacks. As NPR's Ailsa Chang reports, Alexander will be offering information tomorrow on more than 50 terrorism attacks he says were averted.
AILSA CHANG, BYLINE: What you kept hearing from the government today is that finding terrorists is an endless search through countless data points. You need dot after dot so you can connect them all in the end to get an answer. Here's FBI Deputy Director Sean Joyce.
SEAN JOYCE: Investigating terrorism is not an exact science and it's like a mosaic. And we try to take these disparate pieces and bring them together to form a picture.
CHANG: But what the public wants now is which dots of that mosaic were absolutely crucial to finding the bad guys. In the balance between national security and privacy, people now want a balanced sheet so they know how much national security they're getting for every speck of privacy they've lost. Today, General Keith Alexander, the director of the National Security Agency, offered a glimpse of that balance sheet.
KEITH ALEXANDER: In recent years, the information gathered from these programs provided the U.S. government with critical leads to help prevent over 50 potential terrorist events in more than 20 countries around the world.
CHANG: What are those events? As of today, the government offers four. There's Najibulah Zazi, the would-be New York City subway bomber; David Hedley, who was linked to the 2008 Mumbai attacks and a plot to bomb a Danish newspaper office that had published cartoons of the prophet Mohammad. Then there was the Kansas City man who was plotting to bomb the New York Stock Exchange and a San Diego man giving material support to al-Shabab.
Still, House Intelligence chair Mike Rogers wanted Alexander to settle some basic questions.
REPRESENTATIVE MIKE ROGERS: Does the NSA have the ability to listen to Americans' phone calls or read their emails under these two programs?
ALEXANDER: No, we do not have that authority.
ROGERS: Does the technology exist at the NSA to flip a switch by some analyst to listen to Americans' phone calls or read their emails?
CHANG: A big chunk of today's hearing was about calming people down and detailing what officials say is a heavy, almost cumbersome system of checks and balances around the programs. Take the phone records, for example. The government says all of last year, they looked at people's phone records fewer than 300 times. And each time, investigators had to have reasonable clear suspicion that the person had terrorism ties. Deputy Attorney General James Cole says that's not a low bar.
JAMES COLE: If that person is a United States person, a citizen or a lawful permanent resident, you have to have something more than just their own speeches, their own readings, their own First Amendment-type activity.
CHANG: Cole also emphasized that when it comes to Internet monitoring, the government can't target any U.S. citizen or any person known to be in the United States. And that means you can't reverse-target anybody.
COLE: This is where you target somebody who's out of the United States but really your goal is to capture conversations with somebody who is inside the United States. So you're trying to do indirectly what you couldn't do directly. That is explicitly prohibited by this statute.
CHANG: And then, General Alexander says there are the layers of oversight through repeated reports and briefings to every branch of government.
ALEXANDER: This isn't some rogue operation that a group of guys up at NSA are running. This is something that has oversight by the committees, the courts, the administration, and a 100 percent auditable process on a business record, FISA. You know, that's extraordinary oversight.
CHANG: But it's oversight the general public has to take on faith. Alexander says tomorrow he'll be giving lawmakers more information on the 50-some terrorism attacks they've stopped through surveillance programs. But those details will be classified for now. Ailsa Chang, NPR News, The Capitol. Transcript provided by NPR, Copyright NPR.