It is good to be aware of the different types of primaries that you’ll see during the 2018 midterm elections. As a voter, you should know what to expect. If you are also helping with #BlueWave election activities, especially ones outside of your state, it is good to be aware that different types of primaries as they may require different types of strategies.
Voters may cast a vote for any candidate in any party, no matter what party they have registered under. As one example, a Republican could vote for a Democratic candidate. The top vote-getter for each party moves on to the general election.
Voters can only cast votes for candidates in their stated party. So if you are registered as a Democrat, you can only vote for Democratic candidates. The top vote-getter for each party moves on to the general election.
Voters of a particular party assemble at a designated time and openly express their support for one candidate or the other, usually by raising their hand or clustering in groups to be counted. The winner of each party’s caucus moves on to the general election.
Jungle Primary (also known as Top-Two Primary)
Similar to an open primary, voters vote for any candidate they like. The difference is that the top two vote-getters regardless of party move on to the general election. I.e. if the top two vote-getters are both Democrats, then they both move on to the general (and no candidates from other parties are represented.)
For an example of how strategies may need to differ depending on the type of primary, see my post about how jungle primaries can cause problems for parties.