National Mutual Insurance Co. v. Tidewater Transfer Co., Inc.
The Court upheld the constitutionality of 28 U.S.C. §1332(e). §1332(e) treats citizens of United States territories as citizens of a state for the purpose of establishing diversity jurisdiction.
337 U.S. 582 · No. 29 · 1948 term · Vinson Court
Decided Jun 20, 1949 · argued Nov 8, 1948
Judicial power · Miscellaneous judicial power, especially diversity jurisdiction
Majority opinion: Robert Jackson
The voteMajorityDissent
5–45 in the majority, 4 in dissent
4 dissents (5–4)
Reversed. National Mutual Insurance Co. won.
What this ruling means
Reversed: the Supreme Court overturned the decision of the U.S. Court of Appeals, Fourth Circuit, and its own ruling ends the case.
National Mutual Insurance Co. was the petitioner, the side that asked the Supreme Court to review the case. “Won” means the Court gave that side the result it asked for.
From the Supreme Court Database. A justice who agreed with the result but not the reasoning counts in the majority.
Summary
The opening of the case’s Wikipedia article: what the case was about and what the Court held.
National Mutual Insurance Company v. Tidewater Transfer Company, 337 U.S. 582 (1949), was a United States Supreme Court case that upheld the constitutionality of 28 U.S.C. §1332(e). §1332(e) treats citizens of United States territories as citizens of a state for the purpose of establishing diversity jurisdiction.
This case superseded Hepburn v. Ellzey (1805).
Data notes
The text is Wikipedia’s (CC BY-SA 4.0), matched to the case by its citation, docket number or name and year, and is not checked against the opinion. The site keeps the article’s opening section, ending on its last full sentence. The one-sentence summary under the title is the Decisions list’s: Wikipedia’s own ruling sentence, or, tagged “AI-written”, one Claude wrote from this opening.
How the justices voted
Each justice who took part, placed by their Martin–Quinn ideology score for the 1948 term. Filled: the 5 in the majority. Hollow: the 4 in dissent. Colour is the party of the president who appointed them.
Majority(5)
Robert JacksonWrote the majority opinion
Wiley RutledgeWrote a concurrence
Hugo BlackJoined the majority
Frank MurphyJoined the majority
Harold BurtonJoined the majority
Dissent(4)
Felix FrankfurterWrote a dissent
Frederick VinsonWrote a dissent
William DouglasJoined a dissent
Stanley ReedJoined a dissent
Data notes
Each justice’s vote and what they wrote are from the justice-centered file of the Supreme Court Database. “Wrote a concurrence” means the justice sided with the majority and wrote separately; a justice who dissented in part is counted on the side they took overall. A justice who wrote nothing is listed as joining their side.
Positions are each justice’s Martin–Quinn score for the case’s term, the same scores as the Ideology page: negative is more liberal, positive more conservative. A score sums up a justice’s votes across the whole term, so it says where they usually sit, not why they voted as they did here. The median line is the Court’s median justice that term.
The parties
Who brought the case to the Court, who answered it, and how it got there.
- Petitioner
- National Mutual Insurance Co.Insurance company, or surety
- Respondent
- Tidewater Transfer Co., Inc.Trucking company, or motor carrier
- Reached the Court by
- Certiorari (the Court chose to hear it)
- Why it was taken
- Federal appeals courts had ruled differently on the question
Data notes
The names are the two sides of the case’s title. The description under each is the Supreme Court Database’s category for that party, in its own wording. The petitioner is the side that asked the Supreme Court to review the decision below. “Why it was taken” appears only when the majority opinion says lower courts disagreed or were unsure about the question; reasons that would fit any case (“to resolve the question presented”, “an important question”) are left out.
The law at issue
The law the Court was asked to apply, and the kind of power it used to decide.
- Provision
- Article I, Section 8, Paragraph 17 (governance of the District of Columbia and lands purchased from the states)
- Kind of law
- Constitution
- Decided by
- Judicial review (national level); Diversity jurisdiction
Data notes
The Supreme Court Database codes the main constitutional provision, statute or court rule each case turned on, and the basis of the decision: judicial review of a federal or state law, interpreting a statute, supervising the lower courts, and so on. A case can rest on more than one. “Overruled” counts only where the majority opinion says so.
Timeline
What happened at the Court and how the case got there, newest first.
- Jun 20, 1949DecidedDecided · Decided 5–4: reversed. National Mutual Insurance Co. won.
- Nov 8, 1948ArguedArgued · Oral argument before the Court.
- Not datedTaken upTaken up · The Supreme Court agreed to hear the case (certiorari). Federal appeals courts had ruled differently on the question.
- Not datedCourt belowCourt below · Decided by the U.S. Court of Appeals, Fourth Circuit: affirmed, with a dissent.
- Not datedBeganBegan · The case began in the Maryland U.S. District Court.
Data notes
From the Supreme Court Database: the court the case began in, the court whose decision the Supreme Court reviewed and what that court did, how the case came to the Court, and the dates of argument and decision. The database does not date the steps in the lower courts. Court names are the database’s.
Other decisions on the same issue
9 other argued cases since 1946 on miscellaneous judicial power, especially diversity jurisdiction, newest first.
- The Hain Celestial Group v. Palmquist607 U.S. 421Feb 24, 2026 · 607 U.S. 421Judicial power9–0Unanimous band
- Water Splash, Inc. v. Menon137 S. Ct. 1504May 22, 2017 · 137 S. Ct. 1504Judicial power8–0Unanimous band
- Americold Logistics, LLC, v. Conagra Foods, Inc.577 U.S. 378Mar 7, 2016 · 577 U.S. 378Judicial power8–0Unanimous band
- The Hertz Corporation v. Melinda Friend et al.559 U.S. 77Feb 23, 2010 · 559 U.S. 77Judicial power9–0Unanimous band
- Franconia Associates, et al. v. United States536 U.S. 129Jun 10, 2002 · 536 U.S. 129Judicial power9–0Unanimous band
- National City Bank of New York v. Republic of China et al.348 U.S. 356Mar 7, 1955 · 348 U.S. 356Judicial power4–36–3 band
- Lumbermen's Mutual Casualty Co. v. Elbert348 U.S. 48Dec 6, 1954 · 348 U.S. 48Judicial power8–0Unanimous band
- Madruga v. Superior Court of California, in and for the County of San Diego346 U.S. 556Jan 18, 1954 · 346 U.S. 556Judicial power7–27–2 band
- Cope v. Anderson, Receiver331 U.S. 461Jun 2, 1947 · 331 U.S. 461Judicial power8–0Unanimous band
Data notes
Every other orally argued case with a clear vote, from the 1946 term on, that the Supreme Court Database files under the same issue as this one. The database gives each case one issue from a list of about 270 (abortion, search and seizure of vehicles, the death penalty, and so on), whatever law it turned on.
Official record
Read the full opinion on Justia and Wikipedia. Case data from the Supreme Court Database, Version 2026 Release 01, through the 2025 term.