This question didn’t come up much until the last 30 or 40 years.  Almost all people were registered democrat or republican, so almost all people got to vote in the primaries.  Recently, however, there has been a groundswell of people becoming nonaffiliated voters, which is now the largest voting block in Josephine County.  Under a partisan system, these people are not allowed to vote in the primaries for candidates in offices that are designated partisan.  Allowing offices to be nonpartisan ensures that all legal voters in Josephine County have the opportunity to vote for the candidate of their choice.