With the recent kerfuffle over the ‘Statement of Intent” on the Virginia Republican Primary ballot, I’ve heard over and over that we need voter registration by political party in Virginia. That won’t happen because having open primaries is another form of ‘incumbent protection’ so of course the General Assembly isn’t about to pass a law that changes their advantage in primaries.
Thirty-one states have voter registration by party but that doesn’t always mean primary voting is only open to those who registered for a particular party. Which explains the wide variation in party registration in the chart below from the Huffington Post.
Based on nationwide data in 2014, 39% of voters identify as independents, 32% as Democrats and 23% as Republicans. Much more information on the demographics of party identification here.