Proposes a constitutional amendment that changes a valid marriage from a marriage between a man and a woman to two persons regardless of their genders

HJR 166 proposes amending Missouri's state constitution to redefine marriage as a union between "two persons regardless of their genders," replacing the current definition of marriage between "a man and a woman." If approved by voters in a 2026 election, this change would directly affect all marriage licenses issued in Missouri by altering the constitutional basis for marriage. The bill requires voter approval through a referendum scheduled for November 2026 or a special election called by the governor. This is a procedural constitutional amendment, not a law changing current marriage regulations.