- Democratic congressional and state primaries: mixed
- Republican congressional and state primaries: mixed
- Democratic Presidential primary: mixed
- Republican Presidential primary: mixed
- Voters may or may not choose to affiliate with a political party, however, affiliation with a party is required to vote in primary elections.
- 36% of Iowa voters are not affiliated with a political party.
Details of voting in congressional and state primary elections:
- Voters must be registered with a party in order to vote in a primary or caucus, but voters are allowed to change affiliation before the primary election or at the polls on primary day.