"West Marin has nourished my family and me in so many ways," said Steve Kinsey, 43, who formally announced his candidacy Tuesday. "This seems like a chance for me to say thank you to this place."

A director of Marin Conservation League, Kinsey is widely credited with helping to craft Measure V. The successful ballot measure steered future water supplies for Marin Municipal Water District away from imported water and toward conservation.

"He pursued a good ballot initiative, one that controlled growth," said Jerry Friedman of Point Reyes Station, a former planning commissioner who is endorsing Kinsey's candidacy. "He's not knee-jerk. He's a decent environmentalist."

This year, Kinsey and other San Geronimo Valley residents hashed out a compromise with developers of French Ranch, who agreed to leave 95 percent of the subdivision open space and include up to 12 units of senior housing.

"I realize 'compromise' as word has taken on a meaning as something that leaves everyone a little ticked off," he said.

"What I tend to do more than anything else is research," he explained. "The other ingredient is respect. I don't automatically shut off other points of view. I ask, 'What is everyone really after?'"

Previously, Kinsey also negotiated to bring a branch of the county library to the San Geronimo Valley and worked on the long-range development plan for the Lagunitas School District, where his 11-year-old son Breeze is a student.

Bolinas lawyer Dotty LeMieux and former congressional aide John Hess of Larkspur have already declared their candidacies. Judy Arnold, a Novato political consultant, and Corte Madera Councilman Norman Richardson have also been mentioned as potential candidates in the March 26 supervisorial election.

The bulk of Fourth District voters live over the hill -- in Corte Madera and parts of Novato, Larkspur, Mill Valley, and San Rafael.

However, Kinsey suggested that West Marin residency be a prerequisite for representing the district, as the county serves as the immediate governing body for unincorporated West Marin.

West Marin's supervisor, he said, should be "waking up in West Marin air every day."

Kinsey fashions himself a "second-wave" Marin environmentalist. The first wave of environmentalists, like Supervisor Giacomini, fought to protect West Marin's open space through stiff zoning and park acquisitions, he explained.

However, the protection of natural resources should now go hand-in-hand with "creating a healthy community," he said; limited, responsible growth should be allowed (including more second-dwelling units, for instance) to foster economic and demographic diversity.

His own business, he said, specializes in building small houses with recycled materials. Construction is concentrated in areas already built. "There's not a single project I've done that's gone beyond infill," he said.

Kinsey warned that one of the biggest threats -- both to the open space and community diversity --Êis the construction of pricey homes on subdivided agricultural land.

"I hate the trophy-home syndrome," he said, "the whole building of monuments to self-accomplishment."