Government and Court Access to Private-Sector Information
Constitutional limits
The Fourth Amendment governs government searches and generally requires a warrant supported by probable cause, subject to exceptions such as consent, exigency, and plain view. The third-party doctrine (Smith, Miller) permits subpoenas for records voluntarily given to others, but Carpenter requires a warrant for cell-site location information. Riley requires a warrant to search a cell phone.
The ECPA triad
The Wiretap Act regulates interception of communications. The Stored Communications Act governs stored content: a warrant is required for content stored 180 days or less; older content can be obtained by subpoena or a Section 2703(d) order with notice, though many providers demand warrants. The Pen Register Act covers dialing and routing metadata. Preservation letters under Section 2703(f) freeze records pending process. ECPA generally lacks an exclusionary remedy, except under the Wiretap Act.
National security and civil discovery
FISA uses the Foreign Intelligence Surveillance Court; Section 702 targets foreigners abroad with minimization and querying rules. The CLOUD Act addresses overseas-stored data. Civil discovery is bounded by FRCP proportionality, privilege, protective orders, and litigation holds.
Traps
Candidates assume the SCA always requires a warrant, that the third-party doctrine covers cell-site data, or that subpoenas, court orders, and warrants are interchangeable. FISA orders are not ordinary criminal warrants.
Worked example
Police seek six-month-old emails from a provider. Under the SCA, content older than 180 days may be obtained by subpoena with notice, but a warrant is the safest exam answer. Rule of thumb: match legal process to data type and age.