South Dakota voters will decide Constitutional Amendment J on November 3, 2026, a legislatively referred measure that would explicitly disqualify noncitizens from voting in any state or local election or on ballot questions. The Republican-controlled legislature passed the resolution with wide margins earlier in 2025, citing an existing constitutional loophole despite laws already prohibiting noncitizen voting and a related proof-of-citizenship requirement enacted in 2026. In a state with consistent Republican majorities and low documented cases of noncitizen participation, traders assign the measure a 97.4% chance of passage based on historical support for election-integrity amendments. Late developments such as turnout shifts, court rulings on related voting challenges, or unexpected opposition mobilization remain the primary variables that could still alter the outcome before election day.