Bob Derlet, doctor and environmentalist, challenging Rep. Tom McClintock

Rep. Tom McClintock, a longtime lawmaker and favorite of conservatives in California, has repelled repeated challenges – the latest in 2014 from a fellow Republican.

McClintock, of Elk Grove, easily overcame an intraparty showdown with military officer Art Moore. Now, he faces a more traditional opponent in Democrat Bob Derlet, a professor emeritus at UC Davis who formally launched his uphill campaign Monday. A physician, he lives in the Tuolumne County foothills of the Sierra Nevada, not far from Yosemite.

Derlet, 66, is new to politics, and the 4th Congressional District’s lopsided Republican registration likely will make things difficult for him. Just 28 percent of the voters there are registered Democrats, compared with 44 percent who are affiliated with the GOP.

But Derlet, who worked as a primary care doctor at Me-Wuk Indian Health Center in Tuolumne City after spending nearly two decades as director of the emergency room at UC Davis Medical Center in Sacramento, said it was his patients who inspired the bid.

He said he was amazed at the stories they told him about their financial struggles. “I said to myself, ‘Who is representing these people?’ I don’t think Mr. McClintock is,” he said in a brief interview.

In addition to the economy, health care and consumer protection, Derlet said he is passionate about the environment and addressing climate change. He pointed to his many years of research in the Sierra Nevada, sampling water from lakes and streams, and contrasts that experience with the environmental record of McClintock, chairman of the House Natural Resources Subcommittee on Federal Lands.

Derlet said the district, which includes the state’s most important watershed, running from Lake Tahoe to Kings Canyon National Park, needs to be led by environmental champion.

McClintock’s campaign had no comment.

This story was originally published February 22, 2016 at 12:13 PM.