The agency had asked for the new power as early as 1999, the documents show, but had been initially rebuffed because it was not permitted under rules of the US Foreign Intelligence Surveillance Court that were intended to protect the privacy of Americans.
A 2009 draft of an NSA inspector general’s report suggests that contact chaining and analysis may have been done on Americans’ communications data under former US president George W. Bush administration’s program of wiretapping without warrants, which began after the Sept. 11, 2001, attacks to detect terrorist activities and skirted the existing laws governing electronic surveillance.
In 2006, months after the wiretapping program was disclosed by the New York Times, the NSA’s acting general counsel wrote a letter to a senior Justice Department official, which was also leaked by Snowden, formally asking for permission to perform the analysis on US phone and e-mail data.
A Justice Department memo to the attorney general noted that the “misuse” of such information “could raise serious concerns,” and said the NSA promised to impose safeguards, including regular audits, on the metadata program.
In 2008, the Bush administration gave its approval.
A new policy that year, detailed in “Defense Supplemental Procedures Governing Communications Metadata Analysis,” authorized by Secretary of Defense Robert Gates and Attorney General Michael Mukasey, said that because the Supreme Court had ruled that metadata was not constitutionally protected, NSA analysts could use such information “without regard to the nationality or location of the communicants,” according to an internal NSA description of the policy.
After that decision, which was previously reported by the Guardian, the NSA performed the social network graphing in a pilot project for one-and-a-half years “to great benefit,” according to the 2011 memo.
It was put in place in November 2010 in “Sigint Management Directive 424” (sigint refers to signals intelligence).
In the 2011 memo explaining the shift, NSA analysts were told they could trace the contacts of Americans as long as they cited a foreign intelligence justification. That could include anything from ties to terrorism, weapons proliferation or international drug smuggling to spying on conversations of foreign politicians, business figures or activists.
Analysts were warned to follow existing “minimization rules,” which prohibit the NSA from sharing with other agencies names and other details of Americans whose communications are collected, unless they are necessary to understand foreign intelligence reports or there is evidence of a crime. The agency is required to obtain a warrant from the intelligence court to target a “US person” — a citizen or legal resident — for actual eavesdropping.
The documents show that one of the main tools used for chaining phone numbers and e-mail addresses has the code name Mainway.
It is a repository into which vast amounts of data flow daily from the agency’s fiber-optic cables, corporate partners and foreign computer networks that have been hacked.
The documents show that significant amounts of information from the US go into Mainway. An internal NSA bulletin, for example, said that in 2011 Mainway was taking in 700 million phone records per day. In August 2011, it began receiving an additional 1.1 billion cellphone records daily from an unnamed American service provider under Section 702 of the 2008 US FISA Amendments Act, which allows for the collection of the data of Americans if at least one end of the communication is believed to be foreign.