Mississippi Power & Light Co. v. Mississippi ex rel. Moore, Attorney General of Mississippi, et al.
487 U.S. 354 · No. 86-1970 · 1987 term · Rehnquist Court
Decided Jun 24, 1988 · argued Feb 22, 1988
Economic activity · Federal and some few state regulation of public utilities regulation: nuclear power
Majority opinion: John Stevens
The voteMajorityDissent
6–36 in the majority, 3 in dissent
3 dissents (6–3)
Reversed. Mississippi Power & Light Co. lost.
What this ruling means
Reversed: the Supreme Court overturned the decision of the Mississippi Supreme Court, and its own ruling ends the case.
Mississippi Power & Light Co. was the petitioner, the side that asked the Supreme Court to review the case. “Lost” means the Court did not give 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.
Wikipedia has no article on this case, so there is no summary.
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 1987 term. Filled: the 6 in the majority. Hollow: the 3 in dissent. Colour is the party of the president who appointed them.
Majority(6)
John StevensWrote the majority opinion
Antonin ScaliaWrote a concurrence
Byron WhiteJoined the majority
Anthony KennedyJoined the majority
Sandra O'ConnorJoined the majority
William RehnquistJoined the majority
Dissent(3)
William BrennanWrote a dissent
Thurgood MarshallJoined a dissent
Harry BlackmunJoined 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
- Mississippi Power & Light Co.Nuclear power plant or facility
- Respondent
- Mississippi ex rel. Moore, Attorney General of Mississippi, et al.State (Mississippi)
- Reached the Court by
- Certiorari (the Court chose to hear it)
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
- Federal Power
- Kind of law
- Federal Statute
- Decided by
- Statutory construction
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 24, 1988DecidedDecided · Decided 6–3: reversed. Mississippi Power & Light Co. lost.
- Feb 22, 1988ArguedArgued · Oral argument before the Court.
- Not datedTaken upTaken up · The Supreme Court agreed to hear the case (certiorari).
- Not datedCourt belowCourt below · Began in and was decided by the Mississippi Supreme Court: remand.
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
4 other argued cases since 1946 on federal and some few state regulation of public utilities regulation: nuclear power, newest first.
- United States v. Eurodif S. A. et al.555 U.S. 305Jan 26, 2009 · 555 U.S. 305Economic activity9–0Unanimous band
- Huffman et al. v. Western Nuclear, Inc., et al.486 U.S. 663Jun 15, 1988 · 486 U.S. 663Economic activity9–0Unanimous band
- Duke Power Co. v. Carolina Environmental Study Group, Inc., et al.438 U.S. 59Jun 26, 1978 · 438 U.S. 59Economic activity6–36–3 band
- Power Reactor Development Co. v. International Union of Electrical, Radio and Machine Workers, AFL-CIO, et al.367 U.S. 396Jun 12, 1961 · 367 U.S. 396Economic activity7–27–2 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 the argument audio on Oyez. Case data from the Supreme Court Database, Version 2026 Release 01, through the 2025 term.