Arizona Public Service Co. v. Snead

Arizona Public Service Co. v. Snead, 441 U.S. 141 (1979), was a United States Supreme Court decision determining that a New Mexico tax on electricity production violated the Constitution's Supremacy Clause. Snead served as the director of the New Mexico Taxation and Revenue Department.

Background

The majority of electricity produced at the Four Corners Generating Station located in northwest New Mexico is transmitted out of state for sale. In 1975, New Mexico passed the Electrical Energy Tax Act, which levied a tax on electricity generated by power plants amounting to approximately 2% of its retail value. This legislation permitted electric utilities to offset this tax against a 4% gross receipts tax imposed on retail electricity sales, effectively nullifying the tax's effect on electricity consumed within New Mexico. However, electricity produced for export did not have any gross receipts tax liability to counterbalance the energy tax.

A group of five electric companies based outside New Mexico but holding ownership interests in Four Corners—Arizona Public Service Company, Southern California Edison, Public Service Company of New Mexico, Salt River Project, Tucson Electric Power, and El Paso Electric—initiated legal action in Santa Fe County seeking a declaratory judgment that the energy tax was unconstitutional. Notably, Tucson Electric Power held partial ownership of the San Juan Generating Station, while El Paso Electric operated the Rio Grande Generating Station, both facilities situated within New Mexico.

During the pendency of this litigation, Arizona requested the U.S. Supreme Court’s permission to file an original jurisdiction lawsuit against New Mexico concerning the tax; however, the Court declined and directed that the dispute be resolved in state courts.

Following motions for summary judgment, the district court ruled in favor of New Mexico. The electric companies appealed this decision to the New Mexico Supreme Court. While the appeal was underway, Congress enacted the Tax Reform Act of 1976, which included 15 U.S.C. § 391—a provision forbidding states from imposing discriminatory taxes on electricity generation or transmission that impose greater burdens on interstate commerce than on intrastate commerce.

In 1978, the New Mexico Supreme Court upheld the energy tax, reasoning that when considering total taxation—including credits applied against gross receipts taxes—the tax did not discriminate against electricity destined for out-of-state markets. Subsequently, the utilities appealed to the U.S. Supreme Court, contending that the tax violated the Commerce Clause, Export-Import Clause, and federal law under 15 U.S.C. § 391.

Opinion of the Court

The Supreme Court reversed the ruling of the New Mexico Supreme Court and declared the state’s energy tax invalid under the Supremacy Clause because it conflicted with 15 U.S.C. § 391. This federal statute explicitly prohibits state taxation on electricity generation or transmission itself rather than addressing electric companies’ overall tax burdens. Since New Mexico exempted electricity consumed locally but taxed exported electricity without offsetting credits, it directly conflicted with this federal law. The Court underscored Congress’s expansive authority under the Commerce Clause to regulate interstate commerce, referencing landmark decisions such as Katzenbach v. McClung, Heart of Atlanta Motel Inc. v. United States, and Wickard v. Filburn.

In a concurring opinion, Justice Rehnquist, joined by Justice White, observed that although Congress intended 15 U.S.C. § 391 to align with Commerce Clause constraints, in practice, it prohibits taxes like New Mexico’s energy tax.