On December 1, a U.S. District Court struck down Virginia law that mandates open primaries, in some instances. The case is Miller v Brown, 3:05cv-266, e.d. The decision says that when a party is required to hold a primary, then it may impose restrictions on who can vote in that primary. In this particular case, one unit of the Virginia Republican Party (the party unit in one particular State Senate district) has a bylaw, saying no one who voted in any other party’s primary in the last 5 years may vote in the Republican primary, unless that person signs a loyalty pledge to the Republican Party. The decision says that the party bylaw trumps state law, but only when the party is required to hold a primary.

Virginia law lets a party choose whether to have a primary or a convention. But when the office is one in which the party already has an office-holder, then the office-holder, not the party, dictates whether the party should hold a primary or a convention for that office. So, the ruling only applies when the incumbent office-holder is forcing the party to hold a primary.

This case is historic. It is the first time a federal court has ever ruled that parties need not use an open primary, if they don’t wish to. In 2000 the U.S. Supreme Court had said that parties need not use a blanket primary if they don’t wish to, and this year the 9th circuit had said parties need not use a “top-two” primary if they don’t wish to. But those cases had relatively little impact, because so few states use blanket primaries or top-two primaries. But open primaries are very common and are used in approximately 22 states.