“IF YOU’RE an illegal alien in Prince William County, I’d get out,” Corey Stewart, the top local official there, recommended after the victory of Donald Trump. Once Mr. Trump takes office, added Mr. Stewart, who was Mr. Trump’s campaign chairman in Virginia until shortly before the election, “we’re going to find out where each and every one of these guys is, and we’re going to hunt them down and we’re going to deport them.”

Notwithstanding Mr. Stewart’s unbridled enthusiasm for transforming Prince William, a suburban jurisdiction of nearly 450,000, into a game reserve whose quarry is undocumented immigrants, his incendiary rhetoric is unlikely to curry much favor with voters around the state. That may matter to him, since he is in active pursuit of Virginia’s Republican gubernatorial nomination ahead of next year’s elections.

Mr. Stewart, a xenophobe with a disdain for facts, was chosen as Mr. Trump’s state chairman late last year, but proved too radioactive even for the campaign, which dumped him a few weeks before the election. In the end, Virginia was one of the few states where Mr. Trump fared worse than Mitt Romney in 2012.

Having proven itself inhospitable ground for Mr. Trump’s nativist campaign rhetoric, Virginia may take no more kindly to Mr. Stewart’s. Throughout his political career in Prince William, he has evinced a fondness for pressing bombast, often on the theme of illegal immigrants, into the service of headline-hunting.

Soon after he was elected in Prince William a decade ago, he incited a racially charged tempest by pushing legislation to allow the police to inquire about the immigration status of anyone they stopped, for any reason — carte blanche for racial profiling. The police didn’t care for the policy, which alienated Hispanics, and neither did much of the community. Eventually it was relaxed to apply only once an arrest was made, but not before Mr. Stewart had dragged the county through a poisonous culture war. He later credited the policy for driving down crime in Prince William; in fact, the dropoff in the county mirrored a national decline.

Some believed Mr. Stewart was chastened. To the contrary: In his role with the Trump campaign, he delighted in going the candidate himself a toxic step better, often employing a grade-schooler’s political lexicon. He dismissed Mr. Trump’s GOP critics as “establishment pukes,” informed illegal immigrants that Mr. Trump would “kick their asses out of the country” and suggested that his own critics “piss off.”

To that elevated political diction, Mr. Stewart added a dash of venomous recrimination — assigning blame for the shootings of Dallas police officers to Hillary Clinton and Virginia Lt. Gov. Ralph Northam, the front-runner for the Democratic gubernatorial nomination — that was too much even for the Trump campaign. “This guy was a cancer to the organization in Virginia,” said Mike Rubino, Mr. Trump’s top political operative in the state. He added that Mr. Stewart should expect no backing from the president-elect. If that is the case, Mr. Trump would be rendering the commonwealth a service.