The complaint alleged that the New Mexico energy tax was invalid as it placed an unconstitutional burden on interstate commerce in violation of the Commerce Clause, denied Arizona due process and equal protection under the law under the Fourteenth Amendment, and abridged the privileges and immunities guarantied by Article IV, Section 2 of the Constitution.

[1] New Mexico in its reply to the motion argued that the Court should deny the motion as the three Arizona electric companies had filed an action in the district court of Santa Fe County seeking a declaratory judgment that the energy tax was invalid, and that the companies had refused to pay the tax.

The opinion noted, based upon its decisions in Massachusetts v. Missouri, 308 U.S. 1 (1939),[3] and Illinois v. City of Milwaukee, 406 U.S. 91 (1972),[4] that the original jurisdiction of the Supreme Court was to be used only in appropriate cases based upon the seriousness of the case and whether another forum was available with jurisdiction over the parties and where the issues could be litigated.

[1] By using its discretion and limiting the instances where original jurisdiction was granted, the Court could devote its time and resources to its appellate cases.

[1] Because the Arizona electric companies, including the Salt River Project, which is a unit of the Arizona state government, had access to a state court to litigate the issue, Stevens concurred in the judgment.