ORS § 236.217
When any vacancy under ORS 236.215 exists in any partisan elective office of county judge who does not exercise judicial functions or county commissioner occupied by a member of a major political party and that vacancy is to be filled by an appointing authority as provided in ORS 236.215, the major political party pursuant to party rule shall nominate not fewer than three nor more than five qualified persons to fill the vacancy. The nominating procedure shall reflect the principle of one-person, one-vote to accord voting weight in proportion to the number of party members represented. At the request of a party making a nomination, the county clerk or chief elections officer of the county in which the vacancy exists shall assist the party in determining the number of electors registered as members of the party in the electoral district. As soon as the nominees have been appointed, but no later than 20 days after the vacancy occurs, the party shall notify the county clerk of the persons nominated. The county clerk shall notify the remaining members of the county court or board of county commissioners of the county in which the vacancy exists of the nominees.
ORS 236.217