State equal protection jurisprudence will differ from federal when the states take into account the difference in text. The state charters, when originally adopted, did not contain an express “equal protection” clause (note – the California Constitution was amended to add such a clause). Instead, the state constitutions prohibited “special laws” or, more commonly, prohibited the enactment of legislation granting “privileges or immunities” not available to all citizens equally.
Examples of state court decisions involving a privileges or immunities clause on the gay marriage issue include:
Morrison v. Sadler, 821 N.E. 2d 15 (2005) — Indiana Court of Appeals decision upholding state’s Defense of Marriage Act against a “equal privileges or immunities challenge.” Standard of review grants substantial deference to legislative classification and does not apply differing levels of scrutiny.
Standhardt v. Superior Court, 77 P.3d 451 (2004) — Arizona Court of Appeals decision upholding state statute against “privileges or immunities” challenge. The court treated the privileges or immunities clause in the state constitution as merely a state counterpart to the Equal Protection Clause of the 14th Amendment.
Andersen v. King County, 138 P.3d 963 (2006) — Fractured decision of Washington Supreme Court upholding state’s Defense of Marriage Act against a privileges or immunities challenge. The court notes a two-tiered analysis — a higher scrutiny if the “law is a grant of positive favoritism to a minority class.” In all other cases, the court applies a standard federal equal protection analysis.