Responding to my own post!For those who wish to stick to Scripture instead of church history, note that John the Baptist was certainly not a pacifist. When approached about how a soldier should act, he did not recommend leaving the army, but instead regulated how they should act while in the army (Luke 3:14). Later, Jesus Himself praised a centurion whose son He had healed, but did not tell him to leave the military, instead praising the man's faith (Luke 7:8-9).
I am reminded of the story of the 40 Roman soldiers, the "Martyrs of Sevaste," who froze to death on an ice-covered lake rather than renounce their faith. This was after the Edict of Milan--the relevance of which I still have not figured out. Anyway, their story proves that Christians of the 4th century were not universally opposed to military service and thus, violence.
See a version of the story here: 40 Martyrs of Sevaste