OPINION
Appellants-plaintiffs, Charles A. Hoovler, Linda L. Okos, Martin Okos, Patricia Ann Palmer, Robert M. Stwalley, III, and Jeff Symmes, individually and as representatives for and on behalf of all other taxpayers similarly situated (collectively, “the taxpayers”), challenge the constitutionality of P.L. 44-1994, legislation that authorizes an increase in the economic development income tax in Indiana counties and cities falling within certain narrowly-defined population ranges.
We affirm.
FACTS AND PROCEDURAL HISTORY
P.L. 44-1994 allows Indiana counties with a population between 129,000 and 130,600 to increase their economic development income tax rate. Tippecanoe County is currently the only county in Indiana to fall within the stated population range. 1 The taxpayers are Tippecanoe County residents, certified as a class for purposes of this lawsuit, who claim that P.L. 44-1994 violates several of their state and federal constitutional rights. On May 9, 1995, the Tippecanoe Circuit Court declared the statute unconstitutional, finding that it was a local and special law providing for the assessment and collection of taxes for county purposes in violation of Article IV, Sections 22 and 23 of the Indiana Constitution.
The State appealed directly to the Indiana Supreme Court which reversed the trial court and remanded the matter for further proceedings.
State v. Hoovler,
The factual background of this case is set forth in the trial court’s fifteen findings of fact entered in connection with its first judgment and are quoted fully in
Hoovler I.
“16. The only evidence before the Court is that the proceeds of the tax will be used to finance the cleanup of the Tippecanoe County Landfill. However, P.L. 44-1994 does not require the use of the tax revenues collected for substance removal or remedial action at the Landfill, nor does it limit the use of the tax revenues collected to substance removal or remedial action at the Landfill.”
Record at 122 (as amended nunc pro tunc). The trial court then upheld the constitutionality of P.L. 44-1994 and entered judgment in favor of the State.
*741 ISSUES
On appeal, the taxpayers challenge the trial court’s conclusion that P.L. 44-1994 does not violate any of the following constitutional provisions:
I. Article IV, Section 19 of the Indiana Constitution which requires that legislative acts be confined to one subject.
II. The Fourteenth Amendment to the United States Constitution which guarantees equal protection of the laws.
III. Article I, Section 23 of the Indiana Constitution which guarantees equal privileges and immunities to Indiana’s citizens.
IV. Article IV, Section 22 of the Indiana Constitution which prohibits special and local laws regulating county business.
V. Article XI, Section 13 of the Indiana Constitution which prohibits special laws forming corporations.
STANDARD OF REVIEW
“Whether a statute, particularly a tax statute, is wise or expedient is for the legislature to decide, not the courts.”
Taxpayers Lobby of Indiana, Inc. v. Orr,
I. ARTICLE IV, SECTION 19: SINGLE-SUBJECT REQUIREMENT
Article IV, Section 19 of the Indiana Constitution provides: “An act, except an act for the codification, revision or rearrangement of laws, shall be confined to one subject and matters properly connected therewith.” This constitutional provision is intended to guarantee that there is “some rational unity between the matters embraced in the act.”
In re Estate of Wisely,
Article IV, Section 19 was included in the Constitution to protect the legislative process against political log-rolling, “where legislators combine two unrelated bills, each without sufficient support to pass on its own, in order to accumulate the requisite number of votes to pass both.”
Pence v. State,
Despite the lack of political log-rolling, the taxpayers contend that P.L. 44-1994 violates the single-subject requirement in two respects. First, they argue that P.L. 44-1994 impermissibly combines two separate local laws because it contains two population classifications: one applicable to counties with populations between 129,000 and 130,600, and one applicable to cities with populations between 5,650 and 5,708. Second, the taxpayers argue that P.L. 44-1994 violates the single-subject requirement because it contains provisions that amend Title 6 of the Indiana Code regarding taxation and separate provisions that amend Title 36 regarding local government.
The taxpayers’ contentions are based upon an overly strict interpretation of Article IV, Section 19. Our supreme court has given Article IV, Section 19 a much more liberal interpretation as reflected in its recent statement that “[t]he single subject provisions of the Constitution are designed to promote fair practice in legislating without much judicial
*742
intervention.”
Bayh v. Indiana State Bldg, and Constr. Trades Council,
The taxpayers’ single-subject argument is also based upon an overly technical characterization of P.L. 44r-1994. For purposes of Article IV, Section 19, the term “subject” has been held to mean “the thing about which the legislation is had.”
Estate of Wisely,
II. FOURTEENTH AMENDMENT:
EQUAL PROTECTION
The taxpayers next argue that the classifications created in P.L. 44-1994, both by the population parameters and by a provision limiting the legislation’s applicability to qualified sites existing as of July 1, 1994, are not rationally related to any legitimate government interest. Accordingly, argue the taxpayers, P.L. 44-1994 violates the Equal Protection Clause of the Fourteenth Amendment to the United States Constitution. The State responds that any tax classification made in P.L. 44-1994 has already been determined by the supreme court to be rational, and the taxpayers are bound by the law of the case.
The law of the case doctrine “mandates that an appellate court’s determination of a legal issue binds both the trial court and the court on appeal in any subsequent appeal involving the same case and relevantly similar facts.”
St. Margaret Mercy Healthcare Centers, Inc. v. Ho,
It is true that the supreme court talked in terms of a rational relationship between classifications made in P.L. 44-1994 and the subject matter of the legislation.
Hoovler I,
The equal protection guarantee prohibits states from denying “to any person within its jurisdiction the equal protection of the laws.” U.S. Const, amend. XIV, § 1. When reviewing a state statute to determine whether it violates the Equal Protection
*743
Clause, the level of scrutiny used depends upon the classification made in the challenged statute.
Clifft v. Indiana Dep’t of State Revenue,
The taxpayers do not allege that the classifications made in P.L. 44-1994 involve either a suspect class or a fundamental right. Therefore, we examine the legislative classification using the rational basis test.
One of the premises underlying the supreme court’s decision in
Hoovler I,
is that Tippecanoe County is in a situation unlike any other Indiana County.
The same reasoning applies here. Tippecanoe County is not in all relevant respects like any other county in Indiana. It is the only locality in Indiana to have a landfill that the United States Environmental Protection Agency (U.S.E.P.A.) has listed on the U.S. National Priorities List. Record at 120 (Finding of Fact No. 5). In addition, “Tippecanoe County is the only county in Indiana where the county and other local governments have been identified by the U.S.E.P.A. as operators of a ‘Superfund’ site, the Landfill, and, therefore, are potentially responsible parties for the cleanup of the site.” Record at 121-22 (Finding of Fact No. 11). “The situation regarding the cleanup of the Landfill is unique in that the [potentially responsible parties] are cooperating in the funding of the cleanup.” Record at 122 (Finding of Fact No. 13). Furthermore, there is no evidence that any Tippecanoe County taxpayer is being treated differently from any other Tippecanoe County taxpayer.
Outside the tax arena, our supreme court has upheld legislation that treated residents of one county differently from residents of other counties for purposes of voting on re-ferenda concerning whether to allow riverboat gambling in the voters’ respective communities.
Indiana Gaming Comm’n v. Moseley,
*744
The State has an analogous interest here. The residents of Tippecanoe County have more potential exposure to Superfund liability than the residents of any other Indiana county because Tippecanoe County is the site of the only identified Superfund site in Indiana and the only one in which local governmental entities have been identified as operators. The State has an interest in limiting that exposure by providing the governmental operators who have been identified as potentially responsible parties with the tools to further their cooperative efforts in the cleanup process. Singling out Tippecanoe County residents to pay a higher tax to guard against the “staggering” cleanup costs that would result from the potentially responsible parties’ lack of cooperation is rationally related to that interest.
See Hoovler I,
III. ARTICLE I, SECTION 23: EQUAL PRIVILEGES AND IMMUNITIES
Article I, Section 23 of the Indiana Constitution provides: “The General Assembly shall not grant to any citizen, or class of citizens, privileges or immunities, which, upon the same terms, shall not equally belong to all citizens.” The supreme court has determined that equal privileges and immunities claims brought under Article I, Section 23 are to be analyzed separately from claims brought under the equal protection clause of the Fourteenth Amendment.
Collins v. Day,
“First, the disparate treatment accorded by the legislation must be reasonably related to inherent characteristics which distinguish the unequally treated classes. Second, the preferential treatment must be uniformly applicable and equally available to all persons similarly situated.”
Id.
Courts must employ this standard whole giving “substantial deference to legislative discretion.”
Id.
The challenger’s burden is “to negative every conceivable basis which might have supported the classification.”
Id.
(quoting
Johnson v. St. Vincent Hosp., Inc.,
The disparate treatment accorded by P.L. 44-1994 is to permit higher taxes in Tippecanoe County in order to finance remedial action and substance removal. As required by the first step of the Collins analysis, this disparate treatment is reasonably related to inherent characteristics which distinguish the taxpayers. As stated above, the taxpayers are residents of the only county in Indiana with a Superfund site for which the county and other local governmental operators have been identified as potentially responsible parties and who are cooperating in the funding of the landfill cleanup. As the trial court found, Tippecanoe County is “unique,” a fact that distinguishes its residents from the residents of all other Indiana counties. Record at 122 (Finding of Fact No. 13). Furthermore, the higher tax rate is imposed on all Tippecanoe County taxpayers thereby satisfying the second prong of the Collins analysis which requires that the disparate treatment be uniformly applicable and equally available to all persons similarly situated. P.L. 44-1994 does not violate Article I, Section 23 of the Indiana Constitution.
IV. ARTICLE IV, SECTION 22: SPECIAL AND LOCAL LAWS REGULATING COUNTY BUSINESS
The taxpayers contend that P.L. 44-1994 regulates county business in violation of Article IV, Section 22 of the Indiana Constitution. The State contends that the taxpayers’ argument is barred by the law of the case doctrine. We agree with the State.
As previously stated, the law of the case doctrine bars relitigation of all issues decided directly or by implication in a prior decision.
Certain Northeast Annexation Area Landowners,
V. ARTICLE XI, SECTION 13: SPECIAL LAWS FORMING CORPORATIONS
The taxpayers finally contend that the provisions of P.L. 44-1994 forming a local environmental response financing board and district unconstitutionally create a corporation in violation of Article XI, Section 13 of the Indiana Constitution which provides that “[corporations, other than banking, shall not be created by special Act, but may be formed under general laws.” In support of their contention that this constitutional provision has been violated, the taxpayers rely on
Rosencranz v. City of Evansville,
“If an act of a legislature confers special powers and privileges upon the residents or inhabitants of a particular district which cannot be exercised and enjoyed, and the purpose intended by the law carried into effect, without their acting in a corporate capacity, a corporation, to that extent, is created by implication.”
Id.
at 504,
Despite this language in
Rosencranz,
later cases have upheld the creation of local entities for the purpose of public improvements.
See, e.g., Orbison v. Welsh,
Affirmed.
Notes
. P.L. 44-1994 also permits cities with a population between 5,650 and 5,708 to increase their economic development income tax rate. All of the taxpayers' arguments to the trial court, and all but one of their arguments on appeal, concern the county population classification. Both population classifications have the same effect, that is. to treat residents of certain localities differently for tax purposes. Thus, while the focus of the taxpayers’ arguments, and, hence, the focus of our discussion, is on the county population classification, the same principles apply to the city population classification.
. Justice Dickson wrote the lead opinion in which only Justice Selby concurred. Justices Sullivan and DeBruler, however, stated in a concurring opinion that P.L. 44-1994 was a permissible general law. By so stating, Justices Sullivan and DeBruler implied that by virtue of being a general law, P.L. 44-1994 is not a special law. Accordingly, it could not fall within any of the categories of special laws listed in Article IV, Section 22.
