On April 10, Montana filed this brief in the U.S. Supreme Court, in Ravalli County Republican Central Committee v McCulloch, 16-806. The state brief asks the Court not to hear the case. The lower courts had upheld Montana’s open primary, against a challenge by the Republican Party. The lower courts said the party had not shown that letting members of other parties vote in its primary did the party any harm.

A similar case is pending in the U.S. Supreme Court, filed by the Hawaii Democratic Party. The Court will probably act on both cases simultaneously, and should decide in the next few weeks whether to hear these cases.