“What is America?” begins a new trailer USA/Syfy’s The Purge series. “America is, we’ve been told, the land of the free, so tell me then, what is more American than The Purge?” The trailer was unveiled during the show’s panel Saturday at San Diego Comic-Con, which featured producer Jason Blum, Purge creator James DeMonaco, director Anthony Hemingway, producer Brad Fuller, showrunner Tom Kelly, the film’s star Lex Scott Davis and series stars Amanda Warren, Gabriel…