South Dakota's Republican-controlled legislature referred Constitutional Amendment J to the November 3, 2026 ballot by wide margins, explicitly adding noncitizen disqualification language to the state constitution alongside existing age, residency, and citizenship qualifications. Federal law already bars noncitizens from federal elections, and state officials previously identified and removed only a small number of accidental registrations tied to driver's license processes. Similar citizenship requirements passed in multiple states in 2024, reinforcing trader views of strong in-state support for clarifying voter eligibility. The 97.9% implied probability for passage reflects this consensus on straightforward approval. Late shifts remain possible if turnout patterns change or legal challenges to related proof-of-citizenship rules gain traction before election day.