What Is the Powerful Surveillance Law That Divided Lawmakers?

The House on Friday passed a two-year reauthorization of an expiring warrantless surveillance law known as Section 702, reversing course after the bill collapsed days earlier when former President Donald J. Trump urged his allies to “kill” it.

But disappointing privacy advocates, the House narrowly rejected a longstanding proposal to require warrants to search for Americans’ messages swept up by the program.

Here is a closer look.

It is a law that allows the government to collect — on domestic soil and without a warrant — the communications of targeted foreigners abroad, including when those people are interacting with Americans.

Under that law, the National Security Agency can order email services like Google to turn over copies of all messages in the accounts of any foreign user and network operators like AT&T to intercept and furnish copies of any phone calls, texts and internet communications to or from a foreign target.

Section 702 collection plays a major role in the gathering of foreign intelligence and counterterrorism information, according to national security officials.

After the attacks of Sept. 11, 2001, President George W. Bush secretly ordered a warrantless wiretapping program code-named Stellarwind. It violated the Foreign Intelligence Surveillance Act of 1978, or FISA, which generally required a judge’s permission for national security surveillance activities on domestic soil.