Chance Brannon, a U.S. Marine from San Juan Capistrano, had just finished up carrying out a firebombing attack on a Planned Parenthood clinic in Costa Mesa in the early morning of March 13, 2022, when he texted another young man to confirm he’d accomplished the deed. “It’s done,” Brannon said to Xavier Batten, a Florida resident who taught Brannon and his high school friend, Tibet Ergul, of Irvine, how to make the Molotov cocktail they used in the attack. “88,” Batten said in reply. The number is code for “Heil Hitler” among white supremacists, federal prosecutors said. “Did you see...