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International Union of United Automobile, Etc. Workers of America, C. I. O. v. O'Brien

339 U.S. 454 · Decided May 8, 1950 · Supreme Court of the United States

Record summary. This page is generated from the Supreme Court Database’s coded data about the case. It describes who decided what, not the Court’s reasoning. Read the opinion itself before relying on it. Not legal advice.

At a glance

International Union of United Automobile, Etc. Workers of America, C. I. O. v. O'Brien was decided on May 8, 1950 unanimously (9–0). The Court reversed the lower court's decision. Chief Justice Fred M. Vinson wrote the opinion of the Court. SCDB classifies its main issue as “Federal preemption of state legislation or regulation” in the Federalism area.

Read the opinion

Case details

Citations
339 U.S. 454 · 70 S. Ct. 781 · 94 L. Ed. 2d 978 · 1950 U.S. LEXIS 2531
Docket number
456
Decided
May 8, 1950
Argued
March 30, 1950
Court era
Vinson Court
Decision type
Opinion of the Court (orally argued)
Disposition
Reversed
Outcome for petitioner
The petitioning party received a favorable disposition
Vote
9–0 (unanimous)
Majority opinion
Fred M. Vinson
Opinion assigned by
Fred M. Vinson
How the case arrived
Appeal
Issue area
Federalism
Legal provision
Labor-Management Relations Act
Type of law
Federal statute
Decision direction (SCDB)
Liberal what this means

How the Justices voted

Full case caption

International Union of United Automobile, Etc. Workers of America, C. I. O., et al. v. O'Brien, Prosecuting Attorney, et al.

SCDB identifiers: case 1949-071, docket 1949-071-01.

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Source: Supreme Court Database, 2026 Release 01 (data file dated September 8, 2026). Imported into CaseTrail November 5, 2026. Coverage: decisions from the 1946 through 2025 Terms. Methodology · Report an error