Mr. Gonzalez said that quality-of-life issues had been paramount in his decision. He recounted an “eye-opening” moment this year: when he and his family were greeted at the Cleveland airport by two uniformed police officers, part of extra security precautions taken after the impeachment vote.

“That’s one of those moments where you say, ‘Is this really what I want for my family when they travel, to have my wife and kids escorted through the airport?’” he said…

For the Ohioan, Jan. 6 was “a line-in-the-sand moment” and Mr. Trump represents nothing less than a threat to American democracy.

“I don’t believe he can ever be president again,” Mr. Gonzalez said. “Most of my political energy will be spent working on that exact goal.”