The plaintiffs present two issues on this appeal:
1. Does sec. 121.54(2), Stats., as applied to the facts of this case, deny the plaintiffs equal protection of the law as guaranteed by the 14th Amendment of the United States Constitution?
2. Does sec. 121.54(2), Stats., require reasonable uniformity with respect to the maximum distances students are provided publicly financed transportation?
We note, however, the presence of a threshold question in this appeal which has not been briefed by the parties or amicus curiae. This question is whether this court has jurisdiction to determine the constitutional issues raised by the parties.
The plaintiffs commenced this action seeking declaratory relief under sec. 269.56, Stats. (1973), in October, 1974. The purpose of the action was to compel the Mukwonago School District to transport the plaintiffs’ children to Memorial. The statute which is under review in this case is sec. 121.54, Stats. Subsection 121.54(2) (a) generally requires school districts to provide public school students transportation to and from the schools they attend when they live more than 2 *731miles away. This section is not concerned with the location of the school because it is presumed that a public school student living in a particular district will attend a school located within that district. In this manner, statewide uniformity is achieved with respect to public school students. All public school students of this state, with the exception of those residing in cities not required to bus under sec. 121.54(1), Stats., are provided transportation to their school when they live two or more miles away.
Sec. 121.54 (2) (b), Stats., attempts to achieve the same result with respect to private and parochial school students. Again, a minimum distance is specified in this mandatory section, and only private school students residing more than two miles from school can expect publicly financed transportation to and from school. Thus, at first blush, uniformity between public and private school children is achieved: every student, public or private, who lives in a particular school district subject to these mandatory transportation sections, can expect to be provided publicly financed transportation to and from school when they live more than two miles away and when the school attended is within the district. But because private and parochial school attendance areas are not limited geographically by the public school district boundaries of this state, the legislature extended the mandatory provision concerning private schools to include schools situated outside the district boundaries but within a specified distance thereof.
This is the only way in which the mandatory provisions impose a maximum limitation on transportation. Even in this respect the statute does not limit transportation by designating a maximum number of miles a particular student may be transported, but rather by designating how far beyond the boundaries a district *732must transport students. Here, the legislature designated five miles as the limit, and in Young v. Board of Ed., Joint Dist. No. 10, supra, this court said that this designation could not be stretched by statutory construction to accommodate schools, such as Memorial, lying just beyond this distance.
Finally, sec. 121.54(2) (c) permits a school district such as the defendant to provide student transportation on terms other than those specified in the mandatory sections when so authorized by its electorate. In the instant case, however, the electorate of the defendant school district voted not to exercise this option so as to transport the plaintiffs’ children to Memorial.
The plaintiffs’ argument on this appeal is that this statutory plan of providing publicly financed transportation of children attending public and private schools is unconstitutional as applied to the facts of this case: that in failing to exercise the statutorily provided option of providing transportation to children attending a private school more than 5 miles from the district, the electors have acted in a discriminatory and unjustifiable manner. The real thrust and essence of plaintiffs’ argument is that, under the facts of this case, the five mile statutory limitation of sec. 121.54(2) (b)l is an unreasonable and discriminatory classification which denies them equal protection. The constitutionality of this section is clearly at issue here.
When this action was commenced, sec. 269.56(11), Stats. (1973) provided as follows.
“(11) PARTIES. When declaratory relief is sought, all persons shall be made parties who have or claim any interest which would be affected by the declaration, and no declaration shall prejudice the right of persons not parties to the proceeding. In any proceeding which involves the validity of a municipal ordinance or franchise, such municipality shall be made a party, and shall be entitled to be heard, and if the statute, ordinance or *733franchise is alleged to be unconstitutional, the attorney general shall also be served with a copy of the proceeding and be entitled to be heard.” (Emphasis supplied.)
This language, which is repeated verbatim in the new rules of civil procedure, sec. 806.04(11), Stats. (1975), has been strictly interpreted by this court as requiring service on the attorney general whenever the constitutionality of a statute is put in issue in a declaratory judgment action. This section not only recognizes that it is the duty of the attorney general to appear on behalf of the people of this state to show why the statute is constitutional, Chicago & N. W. R. Co. v. LaFollette, 27 Wis.2d 505, 523, 135 N.W.2d 269 (1965), but that the failure to make the attorney general a party to such action operates to prohibit the courts of this state from acquiring the jurisdiction to determine the controversy; McCabe v. City of Milwaukee, 53 Wis.2d 34, 37, 191 N.W.2d 926 (1971).
In several cases in which the court has heretofore applied this section, the declaratory judgment action has been expressly directed to the facial constitutionality of the statute or ordinance. In McCabe v. City of Milwaukee, supra, the owners of lands being condemned by the city commenced a declaratory judgment action seeking a declaration that the condemnation statute was unconstitutional. Their grounds for challenging the constitutionality of the statute was that under the particular facts of that case, the law denied them due process of law. (The landowners received letters informing them of the confirmation of their condemnation awards after the statutory time for appeal had run). Thus, although the relief sought was the declaration that a statute was unconstitutional, the circumstantial basis of the action was the law’s unconstitutional application with respect to these landowners.
*734More recently, this court concluded that it did not have subject matter jurisdiction by reason of the plaintiffs’ failure to comply with sec. 269.56(11), Stats., in Town of Center v. City of Appleton, 70 Wis.2d 666, 235 N.W.2d 504 (1975). In this case, the court more broadly applied the jurisdictional requirement of serving the attorney general. The action brought by the Town of Center against the City of Appleton challenged an ordinance which purported to annex a noncontiguous parcel of land owned by the city but located in the town. The plaintiff town did not explicitly challenge the ordinance on constitutional grounds; rather, the dispute revolved around the issues of whether the “rule of reason” test was applicable to the annexation ordinance and, if so, whether the ordinance passed muster under that test. Nevertheless, because it was not clear whether such an ordinance must meet the “rule of reason” scrutiny as a matter of judicial doctrine (which could be legislatively altered) or as a matter of state constitutional mandate, this court concluded even this threshold question required service on the attorney general because it was “an issue of constitutional dimension.” Town of Center v. City of Appleton, supra at 667-68. Because the attorney general had not been served, the judgment was vacated with directions to dismiss the complaint.
Although none of these cases expressly answers the question with which we are here concerned, they nevertheless set forth several fundamental principles which are applicable to the instant case. First, in litigation which brings into issue the constitutionality of a statute or ordinance, the attorney general has the duty to protect the interests of the state and its citizens, and thus the right to be notified of any declaratory judgment proceedings which might affect those interests. McCabe v. Milwaukee, supra at 37; White House Milk Co. v. *735Thomson, 275 Wis. 243, 247, 81 N.W.2d 725 (1957); sec. 165.25, Stats. (1975). Second, for the purposes of sec. 269.56(11), a declaratory judgment action will he deemed to he a challenge to a statute or ordinance on constitutional grounds even when, as in Town of Center v. City of Appleton, supra, the constitutional issue is collateral to or a preliminary step in the determination of the rights sought to be declared. Finally, because the declaratory judgment action is a creature of statute, this requirement must be strictly complied with in order to vest subject matter jurisdiction in the courts.
We think that cogent reasons exist for the application of the service requirement to this case. First, the substance of this case is without a doubt definitely a constitutional challenge to the statutory plan of public transportation for school children and thus an issue of statewide importance. Second, as the application of the service requirement in Town of Center v. City of Appleton, supra, indicates, the statutory language— “if a statute ... is alleged to be unconstitutional” — is not so narrow as to apply only to those situations where an express request of declaring a statute void on constitutional grounds is made in the proceeding. The purpose of the statute — to afford the attorney general an opportunity to represent statewide concerns — must control over the pleading techniques of the parties.
Having held that the service requirement is applicable to this case, it follows that the trial court was without jurisdiction to try this ease in the absence of service upon the attorney general. Therefore, we cannot review the issues raised in the challenge to the constitutionality of the statutory plan of public transportaton of school children. The case must be remanded to the trial court with directions to set aside the judgment and dismiss *736the plaintiffs’ complaint for the reason that the attorney general was not served with a copy of the proceedings.
By the Court. — Judgment vacated with directions to dismiss the complaint of the plaintiffs without prejudice.