Trumbo came up with the line “I AM SPARTACUS!” in his screenplay. it i s not in the Howard Fast novel SPARTACUS.
I myself prefer “The Gladiators” by Arthur Koestler for a Spartacus novel.
Trumbo also wrote the screenplay for LONELY ARE THE BRAVE in which a military officer Dusalius sends in a military helicopter to hunt down Kirk Douglas in violation of the Posse Comitatus act.
So many of those lefty screenwriters had heavy-handed tendencies towards messaging. An early Trumbo script, for a little b-film, “Sorority House” (1939) even exuded this, with its characters being subserviant to the class-conscious ‘message’ it was hammering. Same thing with Lillian Hellman’s “These Three,” or John Howard Lawson’s “Success at any Price.” Always gets on my nerves when I sense that a character is just a mouthpiece for propaganda, and that’s the norm for those left-wing writers. It’s the way their idiotic brains worked. Revolution first and foremost... human character and drama a side-issue.
Trumbo has a place of honor in, “The Hollywood Party”, Yale University Press.