From Behm v. City of Cedar Rapids (Iowa Jan. 25, 2019):

A number of states have adopted different tests for substantive due process and equal protection claims under their state constitutions when fundamental interests are not implicated. For instance, in South Dakota, the rational basis test utilized in substantive due process requires "a real and substantial relation" between a statute and the objects sought to be obtained. Katz v. S.D. Bd. of Med. & Osteopathic Exam'rs, 432 N.W.2d 274, 278 & n.6 (S.D. 1988). The New Jersey Supreme Court has rejected the federal approach in favor of a balancing test. See Planned Parenthood of Cen. N.J. v. Farmer, 762 A.2d 620, 633-38 (N.J. 2000). The Minnesota Supreme Court has been unwilling to hypothesize a rational basis not asserted in support of a statute, has required that statutory distinctions "must be genuine and substantial," and has stated that there must be "a reasonable connection between the actual ... effect of the challenged classification and the statutory goals." State v. Russell, 477 N.W.2d 886, 888-89 (Minn. 1991) (first quoting Wegan v. Village of Lexington, 309 N.W.2d 273, 280 (Minn. 1981)). The Supreme Courts of Alaska and Vermont have adopted a sliding-scale-type approach to equal protection that can lead to a more stringent review when fundamental interests are not involved. See Alaska Pac. Assurance Co. v. Brown,687 P.2d 264, 269 (Alaska 1984); Baker v. State, 744 A.2d 864, 873 (Vt. 1999).

A body of the academic literature has long recognized and often advocated that states may develop their own equal protection and substantive due process doctrine. See, e.g., Randal S. Jeffrey, Equal Protection in State Courts: The New Economic Equality Rights, 17 Law & Ineq. 239, 356-57 (1999); Jeffrey M. Shaman, The Evolution of Equality in State Constitutional Law, 34 Rutgers L.J. 1013, 1121-23 (2003); Robert F. Williams, Equality Guarantees in State Constitutional Law, 63 Tex. L. Rev. 1195, 1222-24 (1985).

[Likewise, i]n Racing Ass'n of Central Iowa v. Fitzgerald (RACI I), we originally held that the legislature's classification in a taxation statute between land-based casinos and riverboats violated equal protection under the Fourteenth Amendment of the United States Constitution. 648 N.W.2d 555, 558, 562 (Iowa 2002). The United States Supreme Court reversed. Fitzgerald v. Racing Ass'n of Cent. Iowa, 539 U.S. 103, 110, 123 S. Ct. 2156, 2161 (2003). On remand, we held that, notwithstanding the unanimous decision of the United States Supreme Court under the Equal Protection Clause of the Fourteenth Amendment, the classification was nonetheless invalid under article I, section 6 of the Iowa Constitution. RACI II, 675 N.W.2d at 3. Clearly, our approach to equal protection in RACI II had more teeth than that employed by the United States Supreme Court.

An important question in equal protection and due process settings is the role of fact-finding in determining the validity of the classification or legislation. RACI II emphasizes that the legitimate purpose of the classification must be "realistically conceivable" and have "a basis in fact." Id. at 7-8 (emphasis omitted) (first quoting Miller, 394 N.W.2d at 779). On the other hand, we have stated that government "is not required or expected to produce evidence to justify its legislative action." Horsfield Materials, Inc. v. City of Dyersville, 834 N.W.2d 444, 458 (Iowa 2013) (quoting Ames Rental Prop. Ass'n v. City of Ames, 736 N.W.2d 255, 259 (Iowa 2007)).

We think RACI II and Horsfield may be easily reconciled. While the state or municipality is not expected or required to produce evidence to justify its action, a party attacking the classification may do so in an effort to show that the claimed legitimate interest is either not "realistically conceivable" or does not have "a basis in fact." RACI II, 675 N.W.2d at 7-8 (emphasis omitted) (first quoting Miller, 394 N.W.2d at 779). In other words, once the state articulates a legitimate governmental interest that appears plausible on the face of the statute, the burden of coming forward with evidence to attack the asserted justification shifts to the challenger.