NSA officials routinely refer to Presidential Executive Order 12333 as the “foundational” authority for their collection, retention, analysis and dissemination of foreign signal intelligence information. That order serves as a basis for collecting communications by foreign persons that occur outside the United States.
The United States isn’t the only country with an intelligence agency carrying out electronic intercepts on a vast scale, though the United States may be the only country that has multiple forms of internal oversight — executive, congressional and judicial — supervising such operations. The United States may also be one of the few countries that limits, through law, the interception of its citizens’ phone calls or electronic messages unless authorized by a court.
When U.S. citizens’ communications are intercepted by operations aimed at foreign intelligence targets, there are ways to minimize — or remove — their identities.