JUSTICE STEVENS delivered the opinion of the Court.The United States Court of Appeals for the Fifth Circuit declared unconstitutional two sections of a licensing ordinance Page 455 U. S. 285 governing coin-operated amusement establishments in the city of Mesquite, Texas. [Footnote 1] Section 6 of Ordinance 1353, which directs the Chief of Police to consider whether a license applicant has any "connections with criminal elements," [Footnote 2] was Page 455 U. S. 286 held to be unconstitutionally vague.  Section 5, which prohibits a licensee from allowing children under 17 years of age to operate the amusement devices unless accompanied by a parent or legal guardian, [Footnote 3] was held to be without a rational basis.  The first holding rests solely on the Due Process Clause of the Fourteenth Amendment to the United States Constitution.  The Court of Appeals stated that its second holding rested on two provisions of the Texas Constitution, as well as the Fourteenth Amendment to the Federal Constitution.  Because Congress has limited our jurisdiction to review questions of state law, and because there is ambiguity in the Court of Appeals' second holding, we conclude that a remand for clarification of that holding is necessary.  There is, however, no impediment to our review of the first holding.On April 5, 1976, to accommodate the proposal of Aladdin's Castle, Inc. (Aladdin), to open an amusement center in a shopping mall, the city exempted from the prohibition against operation of amusement devices by unattended children certain amusement centers, the features of which were defined in terms of Aladdin's rules, as long as children under the age of seven were accompanied by an adult. [Footnote 4]  Thereafter, Aladdin entered into a long-term lease and made other arrangements to open a center in the mall.  In August, however, Page 455 U. S. 287 its application for a license was refused because the Chief of Police had concluded that Aladdin's parent corporation was connected with criminal elements.  Aladdin then brought suit in a Texas state court and obtained an injunction requiring the city to issue it a license forthwith.  The Texas court found that neither Aladdin nor its parent corporation had any connection with criminal elements, and that the vagueness in the ordinance contravened both the Texas and the Federal Constitutions. [Footnote 5]On February 7, 1977, less than a month after the city had complied with the state court injunction by issuing the license to Aladdin, the city adopted a new ordinance repealing Aladdin's exemption, thereby reinstating the 17-year age requirement, and defining the term "connections with criminal elements" in some detail. [Footnote 6]  Aladdin then commenced this action Page 455 U. S. 288 in the United States District Court for the Northern District of Texas, praying for an injunction against enforcement of the new ordinance.  After a trial, the District Court held that the language "connections with criminal elements," even as defined, was unconstitutionally vague, but the District Court upheld the age restriction in the ordinance. [Footnote 7]  As already noted, the Court of Appeals affirmed the former holding and reversed the latter.Invoking our appellate jurisdiction under 28 U.S.C. § 1254(2), the city now asks us to reverse the judgment of the Court of Appeals.  After we noted probable jurisdiction, 451 U.S. 981, Aladdin advised us that the ordinance reviewed by the Court of Appeals had been further amended in December, 1977, by eliminating the phrase "connections with criminal elements."  The age restriction, however, was retained. [Footnote 8]IA question of mootness is raised by the revision of the ordinance that became effective while the case was pending in the Court of Appeals.  When that court decided that the term "connections with criminal elements" was unconstitutionally vague, that language was no longer a part of the ordinance.  Arguably, if the court had been fully advised, it would have regarded the vagueness issue as moot. [Footnote 9]  It is clear to us, however, that it was under no duty to do so. Page 455 U. S. 289It is well settled that a defendant's voluntary cessation of a challenged practice does not deprive a federal court of its power to determine the legality of the practice.  Such abandonment is an important factor bearing on the question whether a court should exercise its power to enjoin the defendant from renewing the practice, but that is a matter relating to the exercise, rather than the existence, of judicial power. [Footnote 10]  In this case, the city's repeal of the objectionable language would not preclude it from reenacting precisely the same provision if the District Court's judgment were vacated. [Footnote 11]  The city followed that course with respect to the age restriction, which was first reduced for Aladdin from 17 to 7 and then, in obvious response to the state court's judgment, the exemption was eliminated.  There is no certainty that a similar course would not be pursued if its most recent amendment were effective to defeat federal jurisdiction.  We therefore must confront the merits of the vagueness holding."It is a basic principle of due process that an enactment is void for vagueness if its prohibitions are not clearly defined."  Grayned v. City of Rockford, 408 U. S. 104,  408 U. S. 108 (emphasis Page 455 U. S. 290 added). [Footnote 12]  We may assume that the definition of "connections with criminal elements" in the city's ordinance is so vague that a defendant could not be convicted of the offense of having such a connection; we may even assume, without deciding, that such a standard is also too vague to support the denial of an application for a license to operate an amusement center.  These assumptions are not sufficient, however, to support a holding that this ordinance is invalid.After receiving recommendations from the Chief of Police, the Chief Building Inspector, and the City Planner, the City Manager decides whether to approve the application for a license; if he disapproves, he must note his reasons in writing.  The applicant may appeal to the City Council.  If the City Manager disapproved the application because of the Chief of Police's adverse recommendation as to the applicant's character, then the applicant must show to the City Council that "he or it is of good character as a law abiding citizen," which is defined in the ordinance to"mean substantially that standard employed by the Supreme Court of the State of Texas in the Page 455 U. S. 291 licensing of attorneys as set forth in [the Texas statutes]."§ 9 of Ordinance 1353, App. to Juris. Statement 13.  An applicant may further appeal to the state district court.  It is clear from this summary [Footnote 13] that the phrase "connections with criminal elements," as used in this ordinance, is not the standard for approval or disapproval of the application.The applicant's possible connection with criminal elements is merely a subject that the ordinance directs the Chief of Police to investigate before he makes a recommendation to the City Manager either to grant or to deny a pending application.  The Federal Constitution does not preclude a city from giving vague or ambiguous directions to officials who are authorized to make investigations and recommendations.  There would be no constitutional objection to an ordinance that merely required an administrative official to review "all relevant information" or "to make such investigation as he deems appropriate" before formulating a recommendation.  The judgment of the Court of Appeals was therefore incorrect insofar as it held that the directive to the Chief of Police is unconstitutionally vague.IIThe Court of Appeals stated that its conclusion that the age requirement in the ordinance is invalid rested on its interpretation of the Texas Constitution as well as the Federal Constitution:"We hold that the seventeen year old age requirement violates both the United States and Texas constitutional guarantees of due process of law, and that the application of this age requirement to coin-operated amusement centers violates the federal and Texas constitutional guarantees of equal protection of the law."630 F.2d 1029, 1038-1039 (1980) (footnotes omitted).  Page 455 U. S. 292 In the omitted footnotes, the court quoted two provisions of the Texas Constitution that are similar, but by no means identical, to parts of the Federal Constitution. [Footnote 14]Because our jurisdiction of this appeal is based on 28 U.S.C. § 1254(2), we are precluded from reviewing the Court of Appeals' interpretation of the Texas Constitution.  For the federal statute provides:"Cases in the courts of appeals may be reviewed by the Supreme Court by the following methods:""*    *    *    *" "(2) By appeal by a party relying on a State statute held by a court of appeals to be invalid as repugnant to the Constitution, treaties or laws of the United States, but such appeal shall preclude review by writ of certiorari at the instance of such appellant, and the review on appeal shall be restricted to the Federal questions presented. . . ."If the Texas Constitution provides an independent ground for the Court of Appeals' judgment, our possible disagreement with its exposition of federal law would not provide a sufficient basis for reversing its judgment.  If that be so, we should simply dismiss the appeal insofar as the city seeks review of the invalidation of the age requirement.  Cf. United States v. Hastings, 296 U. S. 188,  296 U. S. 193. [Footnote 15]The city contends, however, that the Court of Appeals did not place independent reliance on Texas law, but merely Page 455 U. S. 293 treated the Texas constitutional protections as congruent with the corresponding federal provisions. [Footnote 16]  Under this reading of the Court of Appeals' opinion, our correction of any federal error automatically would result in a revision of the Court of Appeals' interpretation of the Texas Constitution.  Instead of providing independent support for the judgment below, the Texas law, as understood by the Court of Appeals, would be dependent on our reading of federal law.  Although the city's contention derives support from the Court of Appeals' greater reliance on federal precedents than on Texas cases, we nevertheless decline, for the reasons that follow, to decide the federal constitutional question now.It is first noteworthy that the language of the Texas constitutional provision is different from, and arguably significantly broader than, the language of the corresponding federal provisions.  As a number of recent State Supreme Court decisions demonstrate, a state court is entirely free to read its own State's constitution more broadly than this Court reads the Federal Constitution, or to reject the mode of analysis used by this Court in favor of a different analysis of its corresponding constitutional guarantee.  See generally Brennan, State Constitutions and the Protection of Individual Rights, 90 Harv.L.Rev. 489 (1977), and cases cited therein.  Because learned members of the Texas Bar sit on the Court of Appeals for the Fifth Circuit, and because that court confronts questions of Texas law in the regular course of its judicial business, that court is in a better position than are we to recognize any special nuances of state law.  The fact that the Court of Appeals cited only four Texas cases is an insufficient Page 455 U. S. 294 basis for concluding that it did not make an independent analysis of Texas law.Second, it is important to take note of the Court of Appeals' interpretation of the Texas "requirement of legislative rationality."  That interpretation seems to adopt a standard requiring that a legislative classification rests ""upon some ground of difference having a fair and substantial relation to the object of the legislation. . . ."'"  630 F.2d  at 1039. [Footnote 17]  This formulation is derived from this Court's opinion in F. S. Royster Guano Co. v. Virginia, 253 U. S. 412,  253 U. S. 415.  But it is unclear whether this Court would apply the Royster Guano standard to the present case.  See United States Railroad Retirement Bd. v. Fritz, 449 U. S. 166; Craig v. Boren, 429 U. S. 190.  Therefore, it is surely not evident that the Texas standard and the federal standard are congruent.Finally, and of greater importance, is this Court's policy of avoiding the unnecessary adjudication of federal constitutional questions.  As we recently have noted, see Minnick v. California Dept. of Corrections, 452 U. S. 105, this self-imposed limitation on the exercise of this Court's jurisdiction has an importance to the institution that transcends the significance of particular controversies.  No reason for hasty decision of the constitutional question presented by this case has been advanced.  If Texas law provides independent support Page 455 U. S. 295 for the Court of Appeals' judgment, there is no need for decision of the federal issue. [Footnote 18]  On the other hand, if the city is correct in suggesting that the Court of Appeals' interpretation of state law is dependent on its federal analysis, that court can so advise us, and we can then discharge our responsibilities free of concern that we may be unnecessarily reaching out to decide a novel constitutional question. [Footnote 19]The judgment of the Court of Appeals is reversed in part, and the case is remanded for further proceedings consistent with this opinion.It is so ordered
U.S. Supreme CourtCity of Mesquite v. Aladdin's Castle, Inc., 455 U.S. 283 (1982)City of Mesquite v. Aladdin's Castle, Inc.No. 80-1577Argued November 10, 1981Decided February 23, 1982455 U.S. 283SyllabusSection 6 of appellant Texas city's licensing ordinance governing coin-operated amusement establishments directs the Chief of Police to consider whether a license applicant has any "connections with criminal elements."  After receiving recommendations from the Chief of Police, the Chief Building Inspector, and the City Planner, the City Manager decides whether to grant a license.  If he denies the license, the applicant may appeal to the City Council.  If the City Manager denied the application because of the Chief of Police's adverse recommendation as to the applicant's character, the applicant must show to the City Council that he or it is of good character.  Section 5 of the ordinance prohibits a licensee from allowing children under 17 years of age to operate amusement devices unless accompanied by a parent or legal guardian.  After appellant had been ordered in Texas state court proceedings to issue appellee amusement center operator a license (its license application having been initially denied under the predecessor to § 6), and after appellant had repealed appellee's exemption from the predecessor to § 5, appellee brought suit in Federal District Court, praying for an injunction against enforcement of the ordinance.  The District Court held that § 6 was unconstitutionally vague, but upheld § 5.  The Court of Appeals affirmed as to § 6, basing its holding solely on the Due Process Clause of the Fourteenth Amendment, but reversed as to § 5, basing its holding on the Texas Constitution, as well as on the Fourteenth Amendment.Held:1. The fact that the phrase "connections with criminal elements" was eliminated from the ordinance while the case was pending in the Court of Appeals does not render the case moot.  A defendant's voluntary cessation of a challenged practice does not deprive a federal court of its power to determine the legality of the practice.  Here, appellant's repeal of the objectionable language would not preclude it from reenacting the same provision if the District Court's judgment were vacated.  Pp.  455 U. S. 288-289.2. The Court of Appeals erred in holding that § 6 is unconstitutionally vague.  It is clear, from the procedure to be followed when an application for a license is denied by the City Manager based on the Chief of Police's recommendation, that the phrase "connections with criminal elements" is Page 455 U. S. 284 not the standard for approval or disapproval of the application.  Rather, the applicant's possible connection with criminal elements is merely a subject that § 6 directs the Chief of Police to investigate before he makes a recommendation to the City Manager.  The Federal Constitution does not preclude a city from giving vague or ambiguous directions to officials who are authorized to make investigations and recommendations.  Pp.  455 U. S. 289-291.3. Because Congress has limited this Court's jurisdiction to review questions of state law, and because there is ambiguity in the Court of Appeals' holding as to § 5, a remand for clarification of that holding is necessary.  This Court will not decide the federal constitutional question connected with § 5 where (a) the relevant language of the Texas constitutional provisions is different from, and arguably significantly broader than, the language of the corresponding federal provisions; (b) it is unclear whether this Court would apply, as a matter of federal law, the same standard applied as a matter of state law by the Court of Appeals in reviewing § 5; and (c) it is this Court's policy to avoid unnecessary adjudication of federal constitutional questions, there being no need for decision of the federal issue here if Texas law provides independent support for the Court of Appeals' judgment.  Pp.  455 U. S. 291-295.630 F.2d 1029, reversed in part and remanded.STEVENS, J., delivered the opinion of the Court, in which BURGER, C.J., and BRENNAN, MARSHALL, BLACKMUN, REHNQUIST, and O'CONNOR, JJ., joined.  WHITE, J., post, p.  455 U. S. 296, and POWELL, J., post, p.  455 U. S. 297, filed opinions concurring in part and dissenting in part.