Based in Detroit, it is the largest supremacist group, with about 400 members in 32 states, though much of its prominence followed the decay of Aryan Nation and other neo-Nazi groups, experts say. The movement is led by Jeff Schoep, a suit-wearing spokesman for what he calls a “white civil rights movement,” which he views as no different from other groups that defend minorities.

“If we’re a hate group,” said Mr. Schoep in an interview, “then Martin Luther King is a racist or a bigot also.”

Mr. Hall, 32, had embraced the movement and vice versa, earning a loyal following with his energy, unapologetic stands on race and frequent meetings and parties at his home. In recent years, he and other members had staged rallies that sparked street battles in several states, including a skirmish in Pemberton, N.J., during the group’s national conference in April, where rocks, tree branches, folding chairs and pepper spray were used as weapons.

After the fight, Mr. Hall — wearing a black Nazi military uniform — was hungry for more. “That’s why I joined N.S.M.,” Mr. Hall said, his eyes red from Mace. “What a night! I can’t wait for tomorrow!”

Mr. Hall, a garrulous plumber with a cross and a skull tattooed on the back of his shaved head, ran as a National Socialist for a seat on a local water district last fall and won a surprising 28 percent of the vote. He planned to run for office again.

Mr. Schoep has said the group wants to try its hand at more elections, and it has even tried to mimic the populist language used by some candidates during the 2010 campaign, railing against banks receiving “tax-funded federal bailouts” while Americans continue to struggle.