A runoff is necessary because, of the five candidates who ran for supervisor in the June primary election, Mr. Horsley and Ms. Vargas led the field but neither received more than 50 percent of the vote.
Mr. Horsley, 66, received 38.6 percent of the vote. He resides in Emerald Hills and has substantial experience as a local elected official, including 14 years as sheriff — he retired in 2007 — and four years on the board of the Sequoia Healthcare District, a special district that distributes property tax revenues in support of public health.
"I'm aware of what the community's problems are," Mr. Horsley said when asked in an interview why voters should choose him. "I'm aware of how to continue to make this county the best it can possibly be."
April Vargas, 60, is a small business owner from Montara and serves on several county governmental committees, the environmental group Committee for Green Foothills and others. She finished second in the primary with 24.2 percent of the vote.
Ms. Vargas would be the first supervisor in 40 years from the county's coastal community. "I'm definitely the outsider candidate," she said.
"I've been self-employed for 30 years and have had to learn to live within my means," she said in explaining why voters should choose her. "We really need someone (on the board) with a background in business."
Reversing a trend
Public money and how to spend it in hard times will have the close attention of the county's five supervisors. If current trends continue, by 2014 the county will have a structural deficit of $150 million.
In the 2010-11 fiscal year, which began July 1, the county plans to spend $1.8 billion, including $90 million from reserves, continuing a trend of drawing from reserves that began with the 2007-08 budget.
Mr. Horsley's view on getting expenses in line with revenues focuses on public safety and health care — reflective of his experience, he said. Among his cost-saving ideas:
• Have jailed pregnant women sent home where they could be electronically monitored.
• Evaluate patients now in skilled nursing care for less expensive assisted living, and ask nonprofit hospitals to raise their intake of charity cases, given that the national average is 6 percent and locally it's 2 percent.
• Consolidate county firefighting agencies to maintain the number of actual firefighters but lower the number of managers — a savings of about $8 million, Mr. Horsley said.
Ms. Vargas agreed that firefighting management could be consolidated and proposed several other ideas:
• With county pension obligations under-funded by about $1 billion, raise the retirement age and employee contributions to health care and pension benefits, and cap pension benefits for the highest wage earners.
• Reduce the number of managers in county offices. San Mateo County, according to a recent county managers report that Ms. Vargas cited, leads the Bay Area with one manager for every 5.6 employees, compared to 9.6, 9.1 and 8.8 in Santa Clara, Alameda and Contra Costa counties, respectively.
• Reduce the size of the county's vehicle fleet. Ms. Vargas cited a 2010 grand jury report that predicted $1.7 million in savings if drivers used their own vehicles and were reimbursed for their mileage.
If high-speed-rail plans advance as rail authorities envision, there will be more trains running through Atherton, Menlo Park and other Peninsula communities, but they will be electric and run either above or below ground.
Does the Board of Supervisors have a say in how this unfolds?
The county owns the right-of-way and if the rail authority doesn't "do what we want, they can't come in," Mr. Horsley said. The principle issue, he said, is whether to elevate or lower the track. He said he would work toward results that are "sensible and cost-effective but at the same time won't destroy our communities."
"I am in favor of high-speed rail," he added, speaking personally. "It's good for the state of California, good for the nation, and good for San Mateo County."
As for ownership of the railroad right-of-way, San Mateo County is in a Joint Powers Authority with Santa Clara and San Francisco counties, both of which stand to gain with terminal stops in the proposed plan.
The rail authority, Ms. Vargas said, hasn't kept in mind how critical it is to include the people. She recommended that the county take the lead by organizing Peninsula communities on what to support and what to oppose.
"We need three points that we could rally around," she said. "This is a project with major impacts in San Mateo County. Citizens need input on what that looks like and how to come up with the best possible plan."
That approach seemed to work on the coast in the 1990s, she said. While "not exactly analogous," a grass-roots effort convinced state transportation authorities to forego plans for a section of highway around Devil's Slide and instead build a tunnel and protect scenic values, she said.