On February 21, the Idaho House passed HB 439 by 36-32. Current law lets primary voters join the Republican Party on primary day, and then they can vote in the Republican primary. The bill says no one may vote in the Republican primary who has not been a registered member of that party for the last two months.

The bill has less impact on the Democratic primary because the Democratic Party has exercised its option to let independents vote in its primaries.