opinion: Per Curiam.
  Appellee instituted this suit for a declaratory judgment that a 1956 Mississippi statute imposing a charge on public utilities for the use of public streets and places does not apply to it, and, if it does, violates the Federal and State Constitutions. It was tried before a single district judge. After trial the district judge wrote an opinion (154 F. Supp. 736) and then entered a judgment which declared the statute in conflict with the State and Federal Constitutions and thus beyond the power of the Mississippi Legislature to enact. The Court of Appeals for the Fifth Circuit affirmed the judgment of the District Court. 256 F. 2d 83. An appeal was taken to this Court pursuant to 28 U. S. C. § 1254 (2), providing for appeal of a decision of a Court of Appeals where appellant relies on a state statute held to be “invalid as repugnant to the Constitution, treaties or laws of the United States.” Appellee moved to dismiss the appeal, contending that review by appeal does not lie because the Court of Appeals decision declaring the state statute unconstitutional was based on the Constitution of Mississippi as well as the Federal Constitution. Subsequently, appellant moved the Court to vacate the judgment of the Court of Appeals and remand the case to the District Court with instructions to vacate its judgment and convene a three-judge court under 28 U. S. C. §§ 2281 and 2284 to consider appellee’s complaint. Appellee opposed the motion. Without passing judgment on the merits of that motion (cf. Federal Housing Administration v. The Darlington, Inc., 352 U. S. 977), we vacate the judgment of the Court of Appeals and remand the case to the District Court with directions to hold the cause while the parties repair to a state tribunal for an authoritative declaration of applicable state law.
  Proper exercise of federal jurisdiction requires that controversies involving unsettled questions of state law be decided in the state tribunals preliminary to a federal court’s consideration of the underlying federal constitutional questions. See Railroad Comm’n v. Pullman Co., 312 U. S. 496. That is especially desirable where the questions of state law are enmeshed with federal questions. Spector Motor Co. v. McLaughlin, 323 U. S. 101, 105. Here, the state law problems are delicate ones, the resolution of which is not without substantial difficulty— certainly for a federal court. Cf. Thompson v. Magnolia Petroleum Co., 309 U. S. 478, 483. In such a case, when the state court’s interpretation of the statute or evaluation of its validity under the state constitution may obviate any need to consider its validity under the Federal Constitution, the federal court should hold its hand, lest it render a constitutional decision unnecessarily. Railroad Comm’n v. Pullman Co., supra; Spector Motor Co. v. McLaughlin, supra, 104-105. See Leiter Minerals, Inc., v. United States, 352 U. S. 220, 228-229.
  The judgment of the Court of Appeals is vacated and the cause is remanded to the District Court for proceedings in conformity with this opinion.
choices: comity: civil rights comity: criminal procedure comity: First Amendment comity: habeas corpus comity: military comity: obscenity comity: privacy comity: miscellaneous comity primarily removal cases, civil procedure (cf. comity, criminal and First Amendment); deference to foreign judicial tribunals assessment of costs or damages: as part of a court order Federal Rules of Civil Procedure including Supreme Court Rules, application of the Federal Rules of Evidence, Federal Rules of Appellate Procedure in civil litigation, Circuit Court Rules, and state rules and admiralty rules judicial review of administrative agency's or administrative official's actions and procedures mootness (cf. standing to sue: live dispute) venue no merits: writ improvidently granted no merits: dismissed or affirmed for want of a substantial or properly presented federal question, or a nonsuit no merits: dismissed or affirmed for want of jurisdiction (cf. judicial administration: Supreme Court jurisdiction or authority on appeal from federal district courts or courts of appeals) no merits: adequate non-federal grounds for decision no merits: remand to determine basis of state or federal court decision (cf. judicial administration: state law) no merits: miscellaneous standing to sue: adversary parties standing to sue: direct injury standing to sue: legal injury standing to sue: personal injury standing to sue: justiciable question standing to sue: live dispute standing to sue: parens patriae standing standing to sue: statutory standing standing to sue: private or implied cause of action standing to sue: taxpayer's suit standing to sue: miscellaneous judicial administration: jurisdiction or authority of federal district courts or territorial courts judicial administration: jurisdiction or authority of federal courts of appeals judicial administration: Supreme Court jurisdiction or authority on appeal or writ of error, from federal district courts or courts of appeals (cf. 753) judicial administration: Supreme Court jurisdiction or authority on appeal or writ of error, from highest state court judicial administration: jurisdiction or authority of the Court of Claims judicial administration: Supreme Court's original jurisdiction judicial administration: review of non-final order judicial administration: change in state law (cf. no merits: remand to determine basis of state court decision) judicial administration: federal question (cf. no merits: dismissed for want of a substantial or properly presented federal question) judicial administration: ancillary or pendent jurisdiction judicial administration: extraordinary relief (e.g., mandamus, injunction) judicial administration: certification (cf. objection to reason for denial of certiorari or appeal) judicial administration: resolution of circuit conflict, or conflict between or among other courts judicial administration: objection to reason for denial of certiorari or appeal judicial administration: collateral estoppel or res judicata judicial administration: interpleader judicial administration: untimely filing judicial administration: Act of State doctrine judicial administration: miscellaneous Supreme Court's certiorari, writ of error, or appeals jurisdiction miscellaneous judicial power, especially diversity jurisdiction