Is Christian Non-Violence an Essential Teaching?

Our staff is reading The Secret Message of Jesus by Brian McLaren right now. We’re blowing through it pretty fast, but today we finished with Chapter 17 – The Peaceable Kingdom, a chapter on non-violence. McLaren has a few interesting comments about Christian non-violence.

• “Those who are committed to non-violence based on the teachings of Jesus – if they are wrong now – will someday be right.” He’s saying that one day violence will be a thing of the past, and this is part of what God is doing in the world. One day those who are committed to non-violence will be viewed not unlike early abolitionists. They are ahead of their time.
• Every nation who goes to war calls their enemy evil. Jesus commanded us to love our enemy, instead of calling them evil.
• This is the most interesting point he makes: “we need to realize that both our enemies and we ourselves have a common enemy… lust, greed, anger, and hate [that] thrust us into conflict and war… Every warring nation emphasizes the evil of its enemy; few resist the temptation to minimize their own evil. Fewer still realize that the same evils are at work in both ‘them’ and ‘us,’ and therefore pose a common, universal enemy – and it is this universal enemy that the kingdom of God fights with its weapons ‘not of this world.'”

So here’s my question: Is Jesus’s vision for how the kingdom of God will advance opposed to violence? And if it is, then why is Christian non-violence not an essential teaching in contemporary American Christianity? What did the tradition you grew up around teach about violence?