Bill Kortum guided Sonoma County down a new trail.

Kortum, who died Saturday at age 87, saw conservation and environmental protection as important political principles.

As an activist, a strategist and, for a short time, an elected official, he planted them on the public agenda.

Here in his native Sonoma County, the soft-spoken veterinarian built coalitions that elected environmentally oriented candidates, created urban greenbelts to prevent sprawl and established the first open-space program funded by a dedicated sales tax.

Kortum’s influence was felt far beyond the county.

“He was one of the grand old men of the environmental movement in California,” said Sam Schuchat, the executive officer of the California Coastal Conservancy. “It’s hard to imagine a modern California environmental movement without him.”

Beginning in the early 1960s, when he joined a successful campaign to block construction of a nuclear power plant in Bodega Bay, Kortum took a keen interest in coastal development and public access to the Golden State’s famous beaches.

A few years later, he contested the original Sea Ranch proposal, which called for 5,200 homes along the bluffs and private beaches at the northwestern edge of Sonoma County.

A smaller development eventually moved forward, as did an effort backed by Kortum that produced the nation’s first ballot initiative dedicated to coastal protection. Proposition 20, which passed in 1972, was the first step in establishing the California Coastal Commission. The panel regulates seaside development, but it may be best known for fighting celebrities and other wealthy property owners who try to keep citizens off public beaches.

“The highest and best use for the coast is to leave it alone for all citizens to enjoy,” Kortum wrote in response to a Press Democrat editorial in 1975.

Closer to home, his tenure on the Board of Supervisors was cut short by a recall election in 1976. But his election marked a transition in Sonoma County politics, with a majority of Kortum allies elected to the board in the fall, soon followed by the county’s first general plan, which shifted growth into the cities.

Kortum was an early supporter of the open-space district, and, in 1991, he co-founded Sonoma County Conservation Action to advocate for environmental candidates and causes. Its victories include the urban growth boundaries that now safeguard all nine Sonoma County cities from sprawl.

Long before most North Bay leaders, Kortum understood that the public supported a commuter rail system, and he pressed to include it in North Bay congestion relief efforts that had focused solely on adding lanes to Highway 101. Voters rejected several highway-only proposals before approving taxes to pay for highway expansion and commuter rail.

Kortum often said he lost more battles than he won. Maybe so, but his victories made Sonoma County a better place to live. That’s a lasting legacy.