A year and a half into the release of classified documents by Edward Snowden, the existence of far-reaching National Security Agency surveillance is common if controversial knowledge.

But until The Intercept published new documents this month, the role of American companies in that surveillance was less than clear, ProPublicas Julia Angwin and Jeff Larson tell Editor-in-Chief Steve Engelberg in this weeks podcast.

The new documents describe "contractual relationships" between the NSA and unnamed U.S. companies and reveal that the NSA has "under cover" spies working at or with some of them. And indeed, it would be difficult for the NSA to do its work without their help, Larson says.

The important thing about todays communications infrastructure is that it doesnt respect country borders, he says, Youre no longer looking at Soviet signals in Russia youre trying to cast a wide net and collect information thats traveling maybe through the United States while it goes from, say, London to China.

The cooperating companies in question, though unnamed in the new documents, are almost certainly telecommunications companies that lay the fiber for data communications, Angwin says, as they are really the first point of attack for anyone whos trying to do surveillance, whether theyre a criminal, or the NSA.

Aside from privacy concerns, Angwin also notes theres the simple question of cost surveillance has quadrupled to $80 billion since 9/11 vs. benefit. Were, you know, a year and a half into the Snowden leaks, she says, and the NSA has yet to provide clear evidence that any of the surveillance has worked to prevent an attack, right?

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Podcast: When U.S. Companies Help the NSA