While the New Testament calls on followers of Jesus to love, bless and serve our enemies rather than use violence against them, it also acknowledges that God uses the sword-wielding capacity of governments to keep sin in check. For example, four verses after Paul tells disciples to love and serve enemies and to leave all vengeance to God (Rom. 12:17-21), he goes on to say that God orchestrates governments to exact vengeance on wrongdoers (Rom. 13:4). In other words, he’s saying that God will use governments to do things God explicitly forbids disciples of Jesus to do.
In this light, it seems to me there is in principle no inconsistency in a Christian being personally committed to non-violence and yet embracing the opinion that a particular government should in some tragic instances go to war or use violence in other contexts. (I’m not saying I personally believe this, only that there’s no inconsistency in believing this way).
Read the whole thing.