What U.S. learned from listening in on terror group calls

Editor's note: Peter Bergen is CNN's national security analyst and a director at the New America Foundation. David Sterman is a graduate student at Georgetown University's National Security Studies Program.

(CNN) -- Sometime in late 2007, Basaaly Saeed Moalin, a cabdriver living in San Diego, began to have a series of phone conversations with Aden Hashi Ayrow, one of the leaders of Al-Shabaab, a notorious Somali terrorist group.

Moalin had no idea the National Security Agency was listening in.

In one of those phone calls Ayrow urged Moalin to send money to Al-Shabaab, telling him that he urgently needed several thousand dollars.

Peter Bergen

At one point Ayrow told Moalin that it was "time to finance the jihad" and at another, "You are running late with the stuff. Send some and something will happen."

Over several months in 2008, Moalin transferred thousands of dollars to Al-Shabaab.

Moalin even told Ayrow that he could use his house in the Somali capital, Mogadishu, and "after you bury your stuff deep in the ground, you would, then, plant the trees on top."

U.S. prosecutors later asserted that Moalin was offering his house to Al-Shabaab as a place to hide weapons.

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Earlier this year the San Diego cabbie was convicted of conspiracy to provide material support to Al-Shabaab and of money laundering for the terrorist organization.

In 2012, Al-Shabaab ("the Youth" in Arabic) formally announced its merger with al Qaeda. However, there is nothing on the public record to suggest Moalin was planning an attack in the United States.

Another financial supporter of a terrorist group who was detected by NSA surveillance was Khalid Ouazzani, a native of Morocco and a naturalized American living in Kansas City, Missouri.

Sometime in 2008, Ouazzani, who ran Truman Used Auto Parts in Kansas City, swore an oath of allegiance to al Qaeda and, until he was arrested two years later, he sent funds to the terrorist group, providing a total of some $23,000 to al Qaeda.

As revealed Tuesday at a House Intelligence Committee hearing about the NSA's surveillance programs, Ouazzani also had some kind of a "nascent" plan to attack the New York Stock Exchange, according to FBI Deputy Director Sean Joyce. Ouazzani's attorney told CNNMoney he had no part in such a plot, and court documents in his case do not mention any plan to attack the stock exchange.

Al-Shabaab's connection to San Diego and al Qaeda's connection to Kansas City were two of the terrorist conspiracies that were uncovered by NSA surveillance that Joyce and other top national security officials, including the NSA's director, Gen. Keith Alexander, pointed to at Tuesday's hearing as examples of how NSA programs have worked to interrupt terrorist plotting.

These officials otherwise gave no new public information to substantiate the claim that Alexander had made last week that "dozens of terrorist events" had been averted by NSA surveillance, both in the United States and abroad.

On Tuesday, Alexander said he would provide members of the House Intelligence Committee additional information about some 50 other terrorists plots that had been averted in the United States and around the world, but this would be behind closed doors as the details of these plots remain classified.

The public record indicates that few of these are likely to have taken place in the United States. That's because traditional law enforcement methods have overwhelmingly played the most significant role in foiling terrorist attacks, according to a survey of all the jihadist terrorist plots in the United States since 9/11 by the New America Foundation.

Jihadist extremists based in the United States have mounted 43 plots to conduct attacks within the United States since 2001. Of those plots, nine involved an actual terrorist act that was not prevented by any type of government action, such as the 2009 shooting spree by Maj. Nidal Hasan at Fort Hood, Texas, that killed 13.

Of the remaining 34 plots, the public record shows that at least 30 were uncovered by using standard policing practices such as informants, undercover officers and tips to law enforcement.

At Tuesday's hearing, Joyce also pointed to two other plots averted by NSA's programs; the 2009 plots by Najibullah Zazi to bomb the New York subway and by David Coleman Headley to attack a Danish newspaper that had printed cartoons of the Prophet Mohammed.

Alexander had previously cited the Zazi and Headley cases as examples of how the NSA surveillance programs have averted terrorist attacks.

Tuesday's hearing did little to reassure the public that the NSA's surveillance programs have done much to stop terrorist attacks at home, with the major exception of the plot by Zazi to attack the New York subway system around the eighth anniversary of the 9/11 attacks.

As the FBI's Joyce explained at Tuesday's hearing this was "the first core al Qaeda plot since 9/11" that was directed from Pakistan inside the United States.

There is no doubt that it was a serious plot, but if it was the only such serious plot on American soil that the government averted as a result of the NSA's surveillance programs, the public will have to decide whether it justifies the large-scale government surveillance programs -- no matter how carefully they are run so as to respect Americans' civil liberties.

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