Representative Marjorie Taylor Greene of Georgia stepped off a tour bus wrapped in “Trump 2024” decals one afternoon last week in the south-central Virginia with a simple message: Representative Bob Good of Virginia, the chairman of the hard-right House Freedom Caucus, was a traitor to former President Donald J. Trump.

“We need loyalists,” Ms. Greene barked at about a dozen voters gathered on the baking cement of a parking lot in Goochland. Mr. Good, she said, had “kicked Trump when he was down, and went and endorsed another candidate.”

John J. McGuire, a state senator, former Navy SEAL and election denier, is challenging Mr. Good for the Republican nomination on Tuesday. Mr. McGuire, who attended the “Stop the Steal” rally at the Ellipse on Jan. 6, 2021, “is the true MAGA, the true Trumper loyalist!” Ms. Greene said.

Not too far down the road the following evening, Stephen K. Bannon, the former Trump adviser, was on hand to rally with Mr. Good, an important injection of MAGA bona fides for a congressman dealing with the potentially crippling fact that Mr. Trump has endorsed his opponent.

“They think you’re a bunch of morons who don’t count,” Mr. Bannon told a large crowd gathered on a pleasant summer evening in front of the Powhatan Court House, surrounded by rolling farmland. He reminded the audience that Mr. Good was one of eight rebel Republicans who voted last year to oust former Speaker Kevin McCarthy from his post, and he cast the fight for re-election as a battle against the traditional G.O.P.

“Why are we here today?” Mr. Bannon asked. “Because of Kevin McCarthy. We’re here because we were sold out by the Republican establishment. They hate anybody that will stand up to them. This is not about President Trump.”