electronic surveillance
Electronic surveillance is the use of electronic, mechanical, or other devices to collect the contents of wire or electronic communications in situations where at least one party has a reasonable expectation of privacy. The “contents” of a communication include any information about the identity of the parties, or the substance, meaning, or existence of the communication.
Examples include wiretapping, bugging, video surveillance, geolocation tracking via GPS or cell-site data, RFID tracking, internet data mining, and monitoring of online traffic. Surveillance generally falls into two categories: wire communications, which involve transmission over cables or wires, and electronic communications, which include data shared via email, cloud services, or VoIP (voice over internet protocol).
Fourth Amendment Protections and Key Cases
Electronic surveillance can raise Fourth Amendment issues, which protect individuals against unreasonable searches and seizures. In Olmstead v. U.S. (1928), the Supreme Court ruled that wiretapping without physical entry into a home did not constitute a search or seizure. This view changed with Katz v. U.S. (1967), where the Court recognized that the Fourth Amendment protects people, not places, and found that wiretapping a public phone booth violated a reasonable expectation of privacy.
In Kyllo v. U.S. (2001), the Court held that using thermal imaging technology to detect heat signatures inside a home without entry was a search under the Fourth Amendment. The ruling emphasized that surveillance using technology not commonly available to the public can constitute a search if it reveals information that could otherwise only be obtained by entering the home.
Because electronic surveillance qualifies as a search, it typically requires a warrant. To obtain a warrant, law enforcement must show probable cause, specify the communication to be intercepted, and limit the duration of the surveillance. Exceptions include urgent situations involving threats to life, national security, or serious crime conspiracies.
In Carpenter v. U.S. (2018), the Court ruled that accessing historical cell-site location information without a warrant violates the Fourth Amendment. The case highlighted the need to update privacy protections in light of new technologies.
Domestic Surveillance Laws
The Electronic Communications Privacy Act (ECPA) of 1986 governs many forms of electronic surveillance. It allows federal judges to authorize surveillance, including entering a home to install listening devices. Courts have consistently upheld its constitutionality. The ECPA also allows victims of unlawful surveillance to seek damages and court orders to stop or remedy the harm, although they can only sue those who conducted the surveillance, not those who later received the data.
The Communications Assistance for Law Enforcement Act (CALEA) of 1994 requires telecommunications providers to modify their systems to support authorized surveillance efforts.
Foreign Surveillance Laws
While wiretapping foreign nationals for intelligence is controversial, courts agree that warrantless surveillance for domestic security purposes is unconstitutional. The Foreign Intelligence Surveillance Act (FISA) of 1978 which lowers the required evidence required to obtain a surveillance warrant regarding foreign intelligence gathering and describes other procedures for physical and electronic surveillance relating to foreign intelligence.
FISA provisions also apply to American citizens suspected of espionage. It permits warrantless surveillance by the President to protect national security, as long as U.S. citizens are not targeted. Otherwise, federal officials must obtain a warrant from the FISA Court, showing that the target is a foreign power or its agent and that the place being tapped is used by that power.
Following the terrorist attacks on September 11, 2001, the Bush Administration ordered the National Security Agency (NSA) to implement the use of domestic warrantless wiretapping to prevent future terrorist attacks. Some politicians and media outlets have criticized these directives as a violation of the Fourth Amendment and FISA. See, however, emergency powers. In response, Congress passed the Protect America Act of 2007 (PAA), which relaxed certain warrant requirements. Though it expired after six months, many provisions were reauthorized in the FISA Amendments Act of 2008, which underpinned later mass surveillance programs exposed by Edward Snowden.
The Patriot Act and the USA Freedom Act
Passed in 2001, the Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001 (USA Patriot Act) expanded surveillance powers under ECPA and FISA. It allowed longer surveillance periods, removed limits on targeting non-U.S. citizens, and permitted access to voicemail using standard search warrant rules. It also introduced "roving wiretaps," which do not require naming specific service providers or devices, raising concerns under the Fourth Amendment’s Particularity Clause.
Originally set to expire in 2005, the Patriot Act was renewed and amended several times. In 2011, three key provisions were extended: roving wiretaps, business record searches, and surveillance of "lone wolves." These expired in 2015 and were replaced by the Uniting and Strengthening America by Fulfilling Rights and Ending Eavesdropping, Dragnet-collection and Online Monitoring Act (USA Freedom Act), which restored many Patriot Act powers but added some limits, especially on bulk data collection. Civil liberties groups argue that further reforms are still needed.
Recent Developments
Section 702 of FISA authorizes the U.S. government to collect communications of foreign individuals located outside the United States without a warrant. Although the law prohibits intentionally targeting Americans, intelligence agencies routinely sweep up communications involving U.S. citizens in the process.
A "backdoor search" occurs when government agencies, particularly the FBI, access these incidentally collected communications to investigate Americans, bypassing the normal warrant requirements. This practice has drawn criticism for effectively sidestepping Fourth Amendment protections.
In 2025, a federal court ruled that such warrantless searches of U.S. citizens' communications under Section 702 were unconstitutional. The Court emphasized that using foreign intelligence collection as a means to investigate domestic individuals without judicial oversight undermines core privacy rights. While Section 702 remains in force, the ruling marked a significant legal challenge on how intelligence agencies access and use incidentally acquired domestic communications. See: U.S. v. Hasbajrami (2025).
References and Additional Resources
Katz v. U.S., 389 U.S. 347 (1967)
Kyllo v. U.S., 533 U.S. 27 (2001)
Carpenter v. U.S., 585 U.S. 296 (2018)
Electronic Communications Privacy Act of 1986
Foreign Intelligence Surveillance Act of 1978
USA Patriot Act (2001) and USA Freedom Act (2015)
The Guardian - Edward Snowden and the NSA files
NYS Senate Bill S7033 2025-2026 Legislative Session - Re: Algorithmic Surveillance and Pricing
[Last reviewed in July of 2025 by the Wex Definitions Team]
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