He explains that the agency could have installed its tapping gear at the nation’s cable landing stations—the more than two dozen sites on the periphery of the US where fiber-optic cables come ashore. If it had taken that route, the NSA would have been able to limit its eavesdropping to just international communications, which at the time was all that was allowed under US law. Instead it chose to put the wiretapping rooms at key junction points throughout the country—large, windowless buildings known as switches—thus gaining access to not just international communications but also to most of the domestic traffic flowing through the US. The network of intercept stations goes far beyond the single room in an AT&T building in San Francisco exposed by a whistle-blower in 2006. “I think there’s 10 to 20 of them,” Binney says. “That’s not just San Francisco; they have them in the middle of the country and also on the East Coast.”

The eavesdropping on Americans doesn’t stop at the telecom switches. To capture satellite communications in and out of the US, the agency also monitors AT&T’s powerful earth stations, satellite receivers in locations that include Roaring Creek and Salt Creek. Tucked away on a back road in rural Catawissa, Pennsylvania, Roaring Creek’s three 105-foot dishes handle much of the country’s communications to and from Europe and the Middle East. And on an isolated stretch of land in remote Arbuckle, California, three similar dishes at the company’s Salt Creek station service the Pacific Rim and Asia.

Binney left the NSA in late 2001, shortly after the agency launched its warrantless-wiretapping program. “They violated the Constitution setting it up,” he says bluntly. “But they didn’t care. They were going to do it anyway, and they were going to crucify anyone who stood in the way. When they started violating the Constitution, I couldn’t stay.” Binney says Stellar Wind was far larger than has been publicly disclosed and included not just eavesdropping on domestic phone calls but the inspection of domestic email. At the outset the program recorded 320 million calls a day, he says, which represented about 73 to 80 percent of the total volume of the agency’s worldwide intercepts. The haul only grew from there. According to Binney—who has maintained close contact with agency employees until a few years ago—the taps in the secret rooms dotting the country are actually powered by highly sophisticated software programs that conduct “deep packet inspection,” examining Internet traffic as it passes through the 10-gigabit-per-second cables at the speed of light.

According to Binney, one of the deepest secrets of the Stellar Wind program—again, never confirmed until now—was that the NSA gained warrantless access to AT&T’s vast trove of domestic and international billing records, detailed information about who called whom in the US and around the world. As of 2007, AT&T had more than 2.8 trillion records housed in a database at its Florham Park, New Jersey, complex.

Verizon was also part of the program, Binney says, and that greatly expanded the volume of calls subject to the agency’s domestic eavesdropping. “That multiplies the call rate by at least a factor of five,” he says. “So you’re over a billion and a half calls a day.” (Spokespeople for Verizon and AT&T said their companies would not comment on matters of national security.)