Mr. Martin, the retired teacher, who attended the conference, also didn’t care for the Nazi-like salutes, calling them “very foolish.” But he suggested that most of those raising their arms were using the salute as “their version of the middle finger” — a defiant gesture “to the media, to the Trump haters, to everybody they feel alienated from.”

Indeed, the movement has the feel of a dispossessed youth rising up. Hours of interviews with young alt-right leaders suggest a pattern toward their white-nationalist radicalization. Seeing domestic and global strife often rooted in racial and ethnic differences. Finding validation from like-minded people on the internet. Hearing a major presidential candidate echo their grievances.

“The political establishment has made an entire generation of young white men and women into fascists, and that’s a beautiful thing!” said Matthew Heimbach, 25, who runs the Traditionalist Worker Party out of his trailer in Indiana. His group advocates replacing the United States with nation-states based on races, ethnicities and religions.

In Northern California, a university student, felon and Marine veteran, Nathan Damigo, oversees a group called Identity Evropa, which he described as a “fraternity” of mostly young, college-educated men who celebrate European heritage — that is, an embrace of white identity and a rejection of multicultural coexistence.

Ever conscious of the importance of marketing, Mr. Damigo, 30, pointed out that Identity Evropa’s website “looks completely mainstreamed.” And it does, featuring men in business suits who also happen to be sporting the Hitler Youth-style haircut.

But for all the fresh approaches — the slick marketing, the internet savviness — the message remains the same. It is one of separation, of supremacy, of a refusal to recognize the equal worth of others who do not have the same skin tone or share the same religion.

The ascension of the alt-right has lifted some familiar names from the muck of the past, including David Duke, the white nationalist, Holocaust denier and former Louisiana state representative whose national profile has been resurrected.

When a reporter telephoned him recently to discuss the alt-right movement, Mr. Duke wasted little time with a question of his own: “Are you Jewish?”