MO HB2380

Establishes a "closed primary" system in Missouri where voters may only vote in a political party's primary election if they are registered with that party at least 23 weeks (approximately 5.5 months) before the primary election date

Requires candidates seeking a party nomination to be affiliated with that party, as evidenced by voter registration, at least 23 weeks before the candidate filing period opens; independent candidates must be unaffiliated with any established party by the same deadline

Creates a separate ballot for unaffiliated voters containing only ballot measures and nonpartisan candidates from political subdivisions and special districts

Adds political party affiliation as a required data field in voter registration records and allows the information to be included in publicly available voter data provided to candidates, campaigns, and party committees

Takes effect January 1, 2027, with the protected primary system becoming mandatory for primary elections after January 1, 2028; the state is required to pay implementation costs and notify voters of the new requirements