Deeply conservative, they organize online and outside the Republican Party apparatus, engaging in more explicit versions of the chest-beating seen at the president’s rallies.

By Astead W. Herndon

GOLDEN VALLEY, Ariz. — Great American Pizza & Subs, on a highway about 100 miles southeast of Las Vegas, was busier and Trumpier than usual. On any given day it serves “M.A.G.A. Subs” and “Liberty Bell Lasagna.” The “Second Amendment” pizza comes “loaded” with pepperoni and sausage. The dining room is covered in regalia praising President Trump.

But this October morning was “Trumpstock,” a small festival celebrating the president. The speakers included the local Republican congressman, Paul Gosar, and lesser-known conservative personalities. There was a fringe 2020 Senate candidate in Arizona who ran a website that published sexually explicit photos of women without their consent; a pro-Trump rapper whose lyrics include a racist slur aimed at Barack Obama; and a North Carolina activist who once said of Muslims, “I will kill every one of them before they get to me.”

All were welcome, except liberals.

“They label us white nationalists, or white supremacists,” volunteered Guy Taiho Decker, who drove from California to attend the event. A right-wing protester, he has previously been arrested on charges of making terrorist threats.

“There’s no such thing as a white supremacist, just like there’s no such thing as a unicorn,” Mr. Decker said. “We’re patriots.”