HELENA — The U.S. Supreme Court has rejected an appeal seeking to close Montana's Republican primary elections to only GOP-registered voters.

That means the June 7 primaries will be open to all registered voters.

The nation's high court denied without comment Wednesday the appeal by the Montana Republican Party and eight county central committees. The court takes up very few petitions it receives, but in this case, Justice Anthony Kennedy had requested more information about the issue.

GOP attorney Matthew Monforton says that gave him hope the court would intervene, but now he will focus on closing the 2018 primaries.

Party officials say the open-primary system results in crossover voting and prevents them from identifying Republican voters. Their request for an injunction closing this year's primaries was also rejected by two lower courts.