"The US has had four submarines that have been outfitted for these special missions," he said.
But the fibre-optic lines - each no thicker than a quarter - were far more difficult to tap successfully than earlier generations of undersea technology, and interception operations ran the risk of alerting cable operators that their network had been breached.
It's much easier to collect information from any of dozens of cable landing stations around the world - where data transmissions are sorted into separate streams - or in some cases from network operations centers that oversee the entire system, say those familiar with the technology, who spoke on the condition of anonymity to discuss sensitive intelligence matters.
In the aftermath of the September 11 attacks, the NSA said its collection of communications inside the United States was constrained by statute, according to a draft report by the agency's inspector general in 2009, which was obtained by The Washington Post and The Guardian.
The NSA had legal authority to conduct electronic surveillance on foreigners overseas, but the agency was barred from collecting such information on cables as it flowed into and through the United States without individual warrants for each target.
"By 2001, internet communications were used worldwide, underseas cables carried huge volumes of communications, and a large amount of the world's communications passed through the United States," the report said. "Because of language used in the [Foreign Intelligence Surveillance] Act in 1978, NSA was required to obtain court orders to target email accounts used by non-US persons outside the United States if it intended to intercept the communications at a webmail service within the United States. Large numbers of terrorists were using such accounts in 2001."
As a result, after White House and CIA officials consulted with the NSA director, then-President George W. Bush expanded the NSA's legal authority to collect communications inside the United States through a presidential order. The President's Surveillance Program, the report said, "significantly increased [NSA's] access to transiting foreign communications."
General Michael Hayden, then the NSA director, described that information as "the real gold of the program" that led to the identification of threats within the United States, according to the inspector general's report.
Elements of the President's Surveillance Program became public in 2005, when The New York Times reported the government's ability to intercept email and phone call content inside the United States without court warrants, sparking controversy. The FISA court began oversight of those program elements in 2007.
As these debates were playing out within the government, Team Telecom was making certain that surveillance capacity was not undermined by rising foreign ownership of the fibre-optic cables that the NSA was using.
Sign up for CIO Asia eNewsletters.