Instead, following the advice of William Luther Pierce, he quit school and began working at the ANP headquarters in Virginia.

[1] Mason was one of the younger members of the American Nazi Party in 1966, taking inspiration from George Lincoln Rockwell's leadership.

This obsession was inspired by "the Manson Family's attempt to start a race war which they would wait out in the desert; their leader's racism, antisemitism, and female following; and his popularity among rebellious young people, whom Mason hoped to recruit.

[15] In 1973, Mason and fellow neo-Nazi Greg Hurles deployed tear gas against several black teenagers in the parking lot of a Dairy Queen.

"[19] Mason's writings in the Siege newsletter, which have been compiled into a book of the same name, have been credited with forming a large part of the Atomwaffen Division's ideological foundation.

[20] In an interview with Frontline, Mason claimed he was approached by members of the Atomwaffen Division who wished to recruit him as an ideological advisor to which he obliged.

[21] Mason would later mention in a separate interview with MSNBC that members have often disclosed to him their intentions to commit acts of violence, including Sam Woodward, who was later charged with the murder of Blaze Bernstein.

[25][26][27] Mason has also been known to receive foreign admirers in his Denver home, including members of the Nordic Resistance Movement, a proscribed Finnish terrorist organization, and affiliated neo-Nazi music collective "Bolt of Ukko".

[3] In his publication Siege, Mason argued the death of American Nazi Leader, George Lincoln Rockwell was crucial in the adoption of terror tactics.

He claimed that without Rockwell's leadership, National Socialism could no longer function as a legitimate political party, making what he describes as "revolutionary tactics" the only viable option.

In the newsletter, Mason paid tribute to Adolf Hitler, Joseph Tommasi, Charles Manson, and Savitri Devi,[13] and advocated random attacks and murders in order to destabilize society.

[3] In 1992, the newsletters were edited and published in book form as Siege: The Collected Writings of James Mason by Michael Jenkins Moynihan.