n the 1992 decision Planned Parenthood of Southeastern Pennsylvania v. Casey, the U.S. Supreme Court crafted the “undue burden” standard for evaluating the constitutionality of abortion laws. Under that standard, a state is free to regulate abortion, as long as the regulation does not impose an undue burden on a woman’s right to an abortion. Although the standard is disjunctive, the Casey opinion focuses on the “effect” prong of the test, with little guidance as to what a “purpose” prong inquiry would look like. Subsequent Supreme Court abortion jurisprudence has served only to obscure the issue. Circuit courts, therefore, have taken differing approaches to claims that an abortion law was adopted for an invalid purpose.

This Note addresses the divide in how courts evaluate purpose-based challenges under Casey’s undue burden standard. One group of courts— including the Tenth, Fifth, and Eighth Circuits—apply heightened scrutiny to purpose prong challenges, requiring that the state articulate an important governmental interest, which is substantially related to the regulation in question. In contrast, a second group of courts–comprised of the Seventh and Fourth Circuits–apply rational basis review to purpose-based claims, requiring only that the law be rationally related to a legitimate state interest. This Note argues that the application of heightened scrutiny to purpose-based challenges more accurately applies prior Supreme Court abortion precedent, and is more consonant with substantive due process jurisprudence as a whole. It concludes with a discussion of the effect that heightened scrutiny would have on many common abortion laws.