State Primary Systems

State primary elections determine the candidates that will be on the ballot for the general election. States primary election systems vary widely, with some elections only open to voters registered with a particular party, while other states allow non-affiliated voters to participate as well. While most state primary systems are partisan, a few states have adopted nonpartisan primaries, in which voters cast a ballot in a single primary with all candidates on the same ballot. Nonpartisan primary states receive the highest score on our map as evidence suggests these systems increase voter turnout as well as produce more competitive and less polarized elections. Closed primary states receive the lowest score as these systems completely exclude millions of Independent and unaffiliated voters from participating in primary elections.