Exxon Corp. v. Governor of Maryland

437 U.S. 117 (1978)

Quick Summary

Exxon Corp. (plaintiff) and other oil companies contested a Maryland statute prohibiting petroleum producers and refiners from operating retail service stations in the state, alleging it discriminated against interstate commerce and conflicted with federal competition policies. The Governor of Maryland (defendant) defended the statute’s constitutionality.

The dispute revolved around whether such state regulation was permissible under the Commerce and Due Process Clauses of the U.S. Constitution and federal antitrust laws. The Supreme Court upheld the statute, asserting it did not discriminate against or unduly burden interstate commerce, nor was it preempted by federal legislation.

Facts of the Case

In response to the 1973 gas shortage and subsequent complaints regarding unfair distribution practices, the State of Maryland conducted a survey which suggested that petroleum producers and refiners were favoring their own service stations over independent ones in regards to gasoline distribution and pricing.

Consequently, Maryland enacted a statute barring producers or refiners from operating retail service stations within the state. Exxon Corp. (plaintiff), along with other oil companies, initiated a legal challenge against the Governor of Maryland (defendant), claiming that the law discriminated against interstate commerce and was preempted by federal policy promoting competition.

Exxon operated several service stations in Maryland, all of which would be affected by this statute. Independent retailers who also operated within the state would potentially benefit from reduced competition if the major producers and refiners were forced to cease direct retail operations. The case centered on whether Maryland’s statute was constitutional and whether it encroached on federal jurisdiction over interstate commerce and federal antitrust laws.

Procedural Posture and History

  1. Exxon Corp. filed a declaratory judgment action challenging the statute in Maryland’s Circuit Court.
  2. The Circuit Court initially held the statute invalid.
  3. The Maryland Court of Appeals reversed the decision, upholding the statute.
  4. Exxon Corp. appealed to the United States Supreme Court.

I.R.A.C. Format


Whether the Maryland statute that prohibits producers or refiners from operating retail service stations within the state violates the Commerce or Due Process Clauses of the Constitution, or is preempted by federal policy under the Clayton Act as amended by the Robinson-Patman Act.

Rule of Law

The Maryland statute does not discriminate against interstate commerce, does not unduly burden interstate commerce, and does not impose controls on a commercial activity of such an essentially interstate character that it is not amenable to state regulation. Furthermore, states have power to regulate retail gas marketing unless there is a specific federal policy or discrimination against, or burdening of, interstate commerce.

Reasoning and Analysis

The Supreme Court found that the Maryland statute did not discriminate against interstate goods nor favor local producers and refiners because all gasoline sold in Maryland flowed in from out-of-state refineries. The court also determined that while some companies might choose to exit the Maryland market due to the statute, this did not amount to an impermissible burden on interstate commerce as it did not prevent out-of-state companies from entering the market.

Additionally, the court rejected the notion that because petroleum distribution is a national market, states lack the power to regulate its retail aspect. It concluded that neither the Commerce Clause nor federal policies like the Robinson-Patman Act preempted state regulation in this area unless there was clear evidence of discrimination or undue burden on interstate commerce.


The Supreme Court affirmed the judgment of the Maryland Court of Appeals, upholding the validity of the Maryland statute. The court concluded that the statute did not violate either the Commerce or Due Process Clauses of the Constitution and was not preempted by federal policy under the Clayton Act as amended by the Robinson-Patman Act.

Dissenting Opinions

Justice Blackmun dissented in part, arguing that the divestiture provisions of the Maryland law discriminated against interstate commerce by protecting in-state retail service station dealers from out-of-state competition without justification that could not be achieved by less discriminatory means.

Key Takeaways

  1. The Commerce Clause does not protect specific interstate firms but rather the interstate market as a whole from prohibitive regulations.
  2. State regulations are permissible unless they discriminate against or unduly burden interstate commerce or are preempted by a clear federal policy.
  3. The Supreme Court affirmed states’ rights to regulate aspects of commerce such as retail gas marketing in absence of specific federal preemption.

Relevant FAQs of this case

What criteria are used to determine whether a state statute unduly burdens interstate commerce?

To determine if a state statute unduly burdens interstate commerce, the Court evaluates whether the regulation places significant restrictions on transactions across state lines or alters the natural flow of interstate goods disproportionately to any local benefits gained. The balance struck between the burden on interstate commerce and the state’s interest in enacting its legislation is crucial.

  • For example: A state law requiring all trucks entering its borders to be equipped with a specific type of mud flap might be struck down if it imposes substantial costs on out-of-state truckers without significantly improving road safety.

How does a state regulation avoid conflicting with federal antitrust laws?

A state regulation avoids conflicting with federal antitrust laws by not contravening specific federal policies or laws designed to maintain market competitiveness and by serving a legitimate local public interest that justifies its potential impact on competition.

  • For example: If a state passed a law allowing local businesses to collude on prices, it would conflict with federal antitrust laws; however, setting safety standards that apply to all businesses likely would not.

Under what circumstances can a state law be preempted by federal legislation?

A state law can be preempted by federal legislation when Congress has explicitly defined a clear and overarching policy in an area that leaves no room for individual states to supplement or modify it, or when there is an evident conflict between state and federal law such that compliance with both would be impossible.

  • For example: If the federal government establishes unified national standards for vehicle emissions, a state’s attempt to impose less stringent requirements would be preempted by the federal regulations.


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