In a decision issued late Tuesday, justices upheld a lower court ruling and sided with the state Republican Party rather than with Democrats and Secretary of State Ross Miller, who said the Sept. 13 special election should be an open contest.
The ruling is seen as a boon to Mark Amodei, a former state senator who was among 15 Republican contenders still vying for the seat. Republicans feared an unbridled ballot would splinter the Republican vote and allow Democrats to claim the seat for the first time since its creation in 1982.
Mr. Amodei has been endorsed by the state GOP central committee. Democrats have embraced state Treasurer Kate Marshall.
• From wire dispatches and staff reports