## Facts

- The government sought a FISA pen register/trap-and-trace (PR/TT) order for a cellular telephone number used by a subject of an investigation into clandestine intelligence activities.
- The Foreign Intelligence Surveillance Court (FISC) approved the application and the proposed order.
- The order authorized recording and decoding of all “post-cut-through digits,” meaning digits dialed after a call connects, which may include both routing-type information and communication contents (e.g., account numbers or menu responses).
- The order included a restriction: the government could not make affirmative investigative use of post-cut-through digits that constitute contents, unless separately authorized by the FISC.
- The FISC certified to the Foreign Intelligence Surveillance Court of Review (FISCR) a question about whether such an order is authorized by 50 U.S.C. § 1842 and permitted by the Fourth Amendment, given the absence of reasonably available technology to segregate content from non-content at acquisition or immediate processing.
- The FISCR considered briefing from the government and a court-appointed amicus and resolved the certified question in a per curiam opinion.

## Issues

1. Whether 50 U.S.C. § 1842 authorizes a PR/TT order permitting acquisition of all post-cut-through digits when technological limits prevent real-time segregation of content from non-content, if the order bars investigative use of any contents acquired absent separate authorization.
2. Whether the Fourth Amendment prohibits such an order in the foreign-intelligence/national-security context.

## Decision

- The FISCR answered the certified question in the affirmative.
- The court held that § 1842 authorizes an order permitting acquisition of all post-cut-through digits under the stated technological constraints, provided appropriate minimization and use restrictions are imposed.
- The court held that the Fourth Amendment does not prohibit an order of this kind; the surveillance was constitutionally reasonable in the circumstances even without a probable-cause warrant.
- The court emphasized that the order’s prohibition on affirmative investigative use of content-type digits was material to both the statutory and constitutional conclusions.

## Legal Principles

- FISA’s PR/TT framework contemplates that PR/TT collection may, in some circumstances, incidentally acquire contents, and addresses that risk through minimization and use limits rather than categorical prohibition.
- When no reasonably available technology permits separating content from non-content post-cut-through digits at acquisition (or discarding content immediately upon receipt), § 1842 may still permit acquisition of all such digits if minimization measures and restrictions on investigative use of contents are applied.
- Fourth Amendment reasonableness is context-dependent; in the foreign-intelligence and national-security setting, surveillance may be reasonable without meeting the ordinary probable-cause warrant model used for criminal evidence gathering.
- Restrictions limiting the government’s use of incidentally acquired content are relevant safeguards in assessing the overall reasonableness of foreign-intelligence collection.

## Conclusion

The FISCR held that FISA permits a PR/TT order authorizing collection of all post-cut-through digits when technology cannot separate content from non-content in real time, so long as minimization and a bar on investigative use of content-type digits apply; it also held that such collection is Fourth Amendment reasonable in the foreign-intelligence context without a probable-cause warrant.


In re Certified Question of Law, 858 F.3d 591 (FISA Ct. Rev. 2016)