Susan Gorin and John Sawyer long have been rivals on the Santa Rosa City Council, staking out contrasting positions on land use, fiscal issues and neighborhood involvement.
But the election to decide who takes over the 1st District seat on the Sonoma County Board of Supervisors, held for 10 years by Valerie Brown, marks the first time the political opposites have become opponents on the ballot.
The bruising runoff, now more than a year old, is being fought along familiar fronts for the candidates and their dueling political camps.
Gorin is the more liberal figure, supported by the county's largest environmental and labor groups.
Sawyer is the more conservative politician, with support from business and agriculture interests, as well as law enforcement and firefighter unions.
Both claim credentials across that divide, but Gorin accuses Sawyer of "greenwashing" his environmental record, while Sawyer says Gorin's votes against some development have been "short-sighted."
Their rivalry has been bitter at times, factoring in power shifts on the Santa Rosa council and sparking protests by their supporters on the steps of City Hall.
What's different in the race for Brown's seat is that the fight is being waged in what is mostly new geographic terrain for the two candidates.
Both are well-known within Santa Rosa city limits, but the 1st District encompasses a much wider swath of the county to the east and south, including the city of Sonoma and Sonoma Valley.
Since June, when they topped a primary field of four other challengers, all of them from Sonoma Valley or Sonoma, Gorin and Sawyer have been in a high-octane scramble to broaden their bases.
"I think the numbers would show that it's the voters south of Santa Rosa city limits that are going to determine the next supervisor," said Sawyer, 57, who was first elected to the council in 2004 and ran his family's downtown news store for decades until it closed in 2010.
Santa Rosa residents make up 52 percent of the 1st District's voters, but those in Sonoma and Sonoma Valley are more likely to be undecided, the candidates said.
"Santa Rosa voters know the records of John and me, for the most part" said Gorin, 60, a councilmember since being elected in 2006 and a former city planning commissioner and school board member. "Sonoma folks, less so. They're still trying to figure out our core values and voting records."
The campaigns have filled the region's mailboxes, radio waves and farm fields with their messages, an election-season blitz escalating what is already the biggest showdown among local government races.
No other county seats are on the ballot this fall. Supervisors Shirlee Zane and Efren Carrillo easily claimed second terms in the June primary. The Board of Supervisors' two other seats, held by first-term members Mike McGuire and David Rabbitt, are not up for re-election until 2014.
All eyes have turned on the Gorin-Sawyer race, seen as pivotal in determining the direction of county government during a critical period.
It could produce the swing vote on controversial land-use issues and factor heavily in decisions about economic development, pension system overhaul and spending on county services, including roads, parks and open space and aid programs.
"There is a dramatic difference in the direction of the board based on who wins between these two candidates," said David McCuan, a Sonoma State University political scientist.