Heartsick but resolute, political strategist Jimmy Camp hit “send” on an email that will most likely change his life.

“PROMINENT CALIFORNIA GOP CONSULTANT LEAVES REPUBLICAN PARTY”, was the headline, followed by the more traditionally capitalized explanation that he cannot belong to any party led by Donald J Trump.

“Donald Trump is a narcissistic, self-centered, unprincipled, miserable example of a human being,” Camp wrote on Thursday, in an announcement sent out 12 hours or so before the Republican candidate for president would become the official party standard-bearer.

Yet another Republican leaving the party because of Trump’s stands on everything from waterboarding to immigration would not be news except for who Camp is. The southern California strategist has worked for the National Republican Congressional Committee and the California Republican party.

Other clients have included the Utah senator Orrin Hatch and former chairmen of the California GOP, Duf Sundheim and Shawn Steel. In his Thursday announcement, Camp said he had been offered a position in the Trump for President campaign in April but declined.

He joins other prominent Republicans racing away from the real estate mogul who has galvanized the GOP. Conservative columnist George F Will announced in June that Trump had pushed him out of the party he championed for decades.

The Ohio governor, John Kasich, a former Trump rival, has not set foot in the Republican convention even though it’s happening in Cleveland. On Wednesday night, Senator Ted Cruz of Texas took to the convention stage at prime time and refused to endorse the Republican nominee.

It is a sign, said Ethan Rarick, associate director of the UC Berkeley Institute of Governmental Studies, of the continuing deep split in the Grand Old Party, which has been exacerbated both nationally and in California by the controversial billionaire.

“Trump is going to be accepting the nomination tonight, and I didn’t want to spend one day in the party when he’s the leader,” Camp told the Guardian. “That’s why I picked today. It’s very sad. It’s a very sad day. Many of my personal relationships are built around the Republican party … But, once again, I can’t stay a part of a party that would nominate this kind of person.”

Camp’s very first presidential ballot was cast for Ronald Reagan. He did a half-million-dollars worth of business with the California Republican party during the 2014 election cycle. He figures that his consulting work will take a big hit.

But that would not stop him from taking the voter registration card off his refrigerator, he said, filling it out as “decline to state” and turning it in.

“My wife and I talked about it,” Camp said. “We have close friends who are Muslim. What if their son went off the rails and joined Isis? If Trump did what his instinct is, what happens when the car pulls up and takes off our friends to be tortured?”