South Dakota Supreme Court strikes down voter-approved Amendment A on single-subject grounds

On November 24, 2021, the South Dakota Supreme Court issued a 4–1 ruling in Thom v. Barnett striking down Constitutional Amendment A, the recreational cannabis legalization measure that South Dakota voters had approved by 54.18% to 45.82% on November 3, 2020. It marked the first time in U.S. history that a voter-approved statewide recreational cannabis legalization measure was overturned in court.

Why the court nullified the vote

Shortly after the November 2020 election, Highway Patrol Superintendent Rick Miller and Pennington County Sheriff Kevin Thom—with the backing of Governor Kristi Noem—filed suit challenging the amendment under a 2018 addition to the South Dakota Constitution (Article XXIII, Section 1) requiring that no proposed constitutional amendment “embrace more than one subject.”

• The majority’s reasoning: Affirming Circuit Judge Christina Klinger’s February 2021 decision, four justices held that Amendment A covered three distinct subjects—adult-use cannabis legalization, medical cannabis protections, and industrial hemp regulation—and therefore should have been submitted as separate measures.
• The dissent: Justice Scott Myren dissented, writing that all provisions of Amendment A were reasonably germane to the single overarching subject of regulating the cannabis plant.
• What survived and what followed: South Dakota’s statutory medical cannabis initiative, Measure 26 (which passed with nearly 70% on the same 2020 ballot), was unaffected and remained law. However, subsequent statutory attempts by advocates to re-legalize recreational cannabis without medical or hemp language—Measure 27 in 2022 (47.1% Yes) and Measure 29 in 2024 (44.4% Yes)—were both defeated by voters.