## Facts

- Pennsylvania enacted the Pennsylvania Alien Registration Act of 1939, requiring most aliens age 18 or older to register annually, pay a $1 fee, and provide specified information plus additional details as directed by a state agency.
- The state statute required registrants to receive an identification card, carry it at all times, and present it on demand to police or designated state agents.
- Noncompliance carried state criminal penalties, including sanctions for failure to register and separate sanctions for failure to carry or exhibit the card.
- Congress enacted the Federal Alien Registration Act of 1940, establishing a national, federally administered registration system for aliens age 14 or older.
- The federal statute required a single registration, detailed information, fingerprinting, and confidentiality rules limiting disclosure of registration files.
- The federal statute did not require aliens to carry a card or present documentation on demand, and it punished only willful failure to register.
- Aliens sought to enjoin enforcement of the Pennsylvania statute in federal court, arguing it conflicted with federal law; a three-judge district court restrained enforcement.
- State officials appealed; during the appeal, the Supreme Court applied the federal statute enacted while the case was pending.

## Issues

1. Whether the Federal Alien Registration Act of 1940 preempted Pennsylvania’s alien registration statute under the Supremacy Clause.
2. Whether Pennsylvania’s additional registration, fee, and carry-and-exhibit requirements conflicted with Congress’s objectives for a uniform federal alien registration system.

## Decision

- The Supreme Court affirmed the injunction against enforcement of Pennsylvania’s alien registration law.
- The Court held that the federal alien registration statute, considered with federal immigration and naturalization law, constituted a comprehensive federal scheme that precluded competing state alien registration systems.
- The Court concluded the Pennsylvania law conflicted with Congress’s plan because it imposed different and additional obligations on aliens, including annual registration, a fee, and mandatory carry-and-exhibit requirements.
- The Court applied the principle that legislation enacted while a case is pending on appeal may be applied by the appellate court.
- Justice Stone, joined by Chief Justice Hughes and Justice McReynolds, dissented, reasoning that the state law could operate concurrently absent clearer congressional intent to exclude complementary state measures.

## Legal Principles

- Federal law is the supreme law of the land; when Congress establishes rules governing aliens as such, states may not add to or subtract from their force and effect.
- State alien regulation is subject to federal legislative and treaty powers, particularly where the subject bears on foreign affairs and national uniformity.
- A state statute is preempted when it stands as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress (conflict preemption), even without express preemption language.
- A comprehensive federal regulatory scheme may preclude parallel state regimes in the same domain, especially when state requirements alter the federal balance of administration, enforcement methods, and protections.
- Appellate courts apply relevant intervening legislation enacted while an appeal is pending when it governs the dispute.

## Conclusion

The Court held that Congress’s federal alien registration system displaced Pennsylvania’s separate registration regime because the state law interfered with the federally chosen method and objectives for uniform alien regulation, and the Supremacy Clause required that the federal program control.


Hines v. Davidowitz, 312 U.S. 52 (1941)