Oregon is typically known as a bastion of West Coast liberalism, where Democrats are easily elected and a Republican hasn’t served as governor since the early 1980s. But with an unusually competitive three-way contest for governor, the Democratic candidate’s success is hardly a guarantee this year. As mail-in ballots become available to voters next week, Oregon is becoming the unlikely site of one of the most competitive governor’s races in the country. The main reason for the race’s unpredictability is Betsy Johnson, a longtime former Democratic lawmaker with a fondness for salty language who is aiming to become the first...