Novato resident Judy Arnold, the owner of a public relations firm and a former supervisor's aide, formally declared her candidacy Tuesday in the race for West Marin supervisor.

Arnold, 55, who lived 13 years in Point Reyes Station, is the fourth candidate running to succeed incumbent Gary Giacomini. Giacomini is retiring after six terms.

Joining Arnold on the March 26 ballot will be lawyer Dotty LeMieux of Bolinas, architect Steve Kinsey of Forest Knolls, and a former aide to Senator Barbara Boxer, John Hess of Larkspur.

"The most important thing in this race is the character and personality of the person running," Arnold said. "I understand what the job is. I know how to do it. I want to do it."

Of the four candidates, Arnold is the most clearly identified with Giacomini. She ran his first campaign in 1972 and worked as his aide the next two years.

"I really do think I will follow in the best of [Giacomini's] tradition," she said.

Of that period 20 years ago, Arnold said she "stood in front on A-60 [agriculture, one house-per-60 acres] zoning when that was a revolution."

These days, she said, one of the main tasks for a supervisor is to ensure the efficient flow of county services - fire protection, law enforcement, libraries, roadwork - in an era of tight budgets. "I understand that [those services] have to be there," she said.

Arnold, who is a director of the Marconi Conference Center, worked for the last two years as director of communications and fund development for Goodwill Industries of the Redwood Empire.

When Giacomini announced his retirement last spring, Arnold quit her post at Goodwill so she could campaign for his job.

Arnold and her husband Bruce lived in Point Reyes Station for 13 years ending in 1989. During that time, Arnold said, she helped found the Point Reyes Station Village Association and served as its first president.

She also helped found the West Marin Alliance, a short-lived group in the 1980s representing local nonprofit and planning groups.

The Fourth Supervisorial District includes all of West Marin plus parts of Novato, San Rafael, Corte Madera, and Larkspur, with the over-the-hill areas comprising the majority of voters.