opinion: Mr. Justice Jackson
  delivered the opinion of the Court.
  The appellants sought review by this Court of a decision by the Supreme Court of Utah on the ground that the State convicted them in violation of the Fourteenth Amendment to the Federal Constitution. In the trial court a motion to dismiss the charge at the close of the evidence broadly indicated reliance on the Fourteenth as well as the First Amendment, and such reliance was indicated in requests for instructions. A preliminary motion to quash the information was stated in broad terms which it is claimed admitted argument of any federal grounds. Trial resulted in conviction and the Supreme Court of the State overruled all constitutional objections and affirmed.
  On argument in this Court, inquiries from the bench suggested a federal question which had not been specifically assigned by defendants in this Court, nor in any court below, although general transgression of the Fourteenth Amendment had been alleged. This question is whether the Utah statute, for violation of which the appellants are amerced, is so vague and indefinite that it fails adequately to define the offense or to give reasonable standards for determining guilt. The question grew out of these circumstances:
  Defendants were tried on an information which charged violation of § 103-11-1, Utah Code Ann. 1943, in that they conspired “to commit acts injurious to public morals as follows, to-wit: . . . It then specified acts which amount briefly to conspiring to counsel, advise, and practice polygamous or plural marriage, and it set forth a series of overt acts in furtherance thereof. The Supreme Court considered that the prosecution was under Paragraph (5) of 103-11-1 which, so far as relevant, defines conspiracy, “(5) to commit any act injurious to the public health, to public morals, or to trade or commerce, or for the perversion or obstruction of justice or the due administration of the laws . . . .”
  It is obvious that this is no narrowly drawn statute. We do not presume to give an interpretation as to what it may include. Standing by itself, it would seem to be warrant for conviction for agreement to do almost any act which a judge and jury might find at the moment contrary to his or its notions of what was good for health, morals, trade, commerce, justice or order. In some States the phrase “injurious to public morals” would be likely to punish acts which it would not punish in others because of the varying policies on such matters as use of cigarettes or liquor and the permissibility of gambling. This led to the inquiry as to whether the statute attempts to cover so much that it effectively covers nothing. Statutes defining crimes may fail of their purpose if they do not provide some reasonable standards of guilt. See, for example, United States v. Cohen Grocery Co., 255 U. S. 81. Legislation may run afoul of the Due Process Clause because it fails to give adequate guidance to those who would be law-abiding, to advise defendants of the nature of the offense with which they are charged, or to guide courts in trying those who are accused.
  When the adequacy of this statute in these respects was questioned, the State asked and was granted reargument here. Rehearing convinces us that questions are inherent in this appeal which were not presented to or considered by the Utah Supreme Court and which involve determination of state law. We recognize that the part of the statute we have quoted does not stand by itself as the law of Utah but is part of the whole body of common and statute law of that State and is to be judged in that context. It is argued that while Paragraph (5) as quoted is admittedly very general, the present charge is sustainable under Paragraph (1) thereof which makes a crime of any conspiracy to commit a crime and that the sweep of Paragraph (5) is or may be so limited by its context or by judicial construction as to supply more definite standards for determining guilt. It is also said that the point, so far as this case is concerned, has been waived or lost because there was no timely or sufficient assignment of it as ground for dismissal to comply with state practice. We believe we should not pass upon the questions raised here until the Supreme Court of Utah has had opportunity to deal with this ultimate issue of federal law and with any state law questions relevant to it.
  This trial was not conducted in federal court nor for violation of federal law. It is a prosecution by the State, in its courts, to vindicate its own laws. Our sole concern with it is to see that no conviction contrary to a valid objection raised under the Fourteenth Amendment is upheld. What the statutes of a State mean, the extent to which any provision may be limited by other Acts or by other parts of the same Act, are questions on which the highest court of the State has the final word. The right to speak this word is one which State courts should jealously maintain and which we should scrupulously observe. In order that the controversy may be restored to the control of the Supreme Court of Utah, its present judgment is vacated and the cause is remanded for proceedings not inconsistent herewith.
  Vacated and remanded.
  Mr. Justice Black concurs in the result.
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