for starters there shouldn’t be any open primaries—only registered GOP can vote in GOP primary —dems should be the same way.
Nest reduce the number of primary election dates from 15 to 1. I am sick of giving Iowa and NH and SC so much say so in who will be the GOP presidential candidate.
Some places have no “Party” voter registration.
You may want to go to the following site and scan for the states with open/closed
primaries, etc. It’s a mixed bag amongst the states for sure. Scroll down to
the bottom for a listing by state.
http://www.brennancenter.org/sites/default/files/publications/VRM%20Party%20Affiliation.pdf