NSA ends a controversial part of its warrantless spying

WASHINGTON — The National Security Agency is stopping one of the most disputed forms of its warrantless surveillance program in which it collects Americans' emails and texts to and from people overseas and that mention a foreigner under surveillance, according to officials familiar with the matter.

National security officials have argued that such surveillance is lawful and helpful in identifying people who might have links to terrorism, espionage or otherwise are targeted for intelligence-gathering. The fact that the sender of such a message would know an email address or phone number associated with a surveillance target is grounds for suspicion, these officials argued.

But privacy advocates argue that such broad collection of information means the agency, with help from telecommunications companies, is intercepting communications based on what they say, rather than who has sent or received it.

The existence of this so-called "about the target" collection was first reported by The New York Times in 2013.

The NSA made the change to resolve problems it was having complying with special rules imposed by the Foreign Intelligence Surveillance Court in 2011 to protect Americans' privacy. For technical reasons, the agency ended up collecting messages sent and received domestically as a byproduct of such surveillance, the officials said.

The problem stemmed from certain bundled messages that internet companies sometimes packaged together and transmitted as a unit. If even one of them had a foreign target's email address somewhere in it, all were sucked in.

After the NSA brought that issue to the court's attention in 2011, a judge ruled that it violated the Fourth Amendment, which bars unreasonable searches. The agency then proposed putting the bundled messages in a special repository to which analysts, searching through intercepts to write intelligence reports, would generally not have access. The court permitted that type of collection to continue with that restriction.

But last year, officials said, the NSA discovered that analysts were querying the bundled messages in a way that did not comply with those rules. The agency brought the matter to the court's attention, resulting in a delay in reauthorizing the broader warrantless surveillance program until the agency proposed ceasing this collection practice.