Christian Pacifism

A simple question:

Is there any biblical authority for a Christian engaging in any physical violence whatsoever?

We're currectly studying the sermon on the mount in my wednesday night class, and we came to the section regarding non-resistance--turn the other cheek, go a second mile, lend, etc. i was just really surprised at the number of people in the class who offered comments trying to justify returning physical violence if attacked.

i say that, but the truth is, i guess i'm not really surprised. it has been deeply culturally engrained even in me that there's a point at which if you do not return physical violence then there is something wrong with you, something "weak" about you, something even dishonorable or unethical about you. and i'm sure a lot of sentiments in those comments last night arose from such cultural conditioning. and i must admit the strong pull of such cultural conditioning because even i struggle to answer when asked about certain scenarios. Would i physically fight someone who intended to harm my family? Would i let my child watch someone beat me to a pulp without ever fighting back? The trouble with such questions is that they are playing on my own inclination and will, they are not getting at what should be done or ought to be done. Simply because i would do something or have a strong tendency toward doing something, that doesn't imply that my action or tendency is right.

Last night's comments largely centered around the sentiment that surely there's some point at which it's not okay to let yourself get walked all over. There was more than one appeal to common sense, "surely that's why God blessed us with common sense--to know that we're not just supposed to sit there and take it."

So why did Jesus just sit there any take it? Were his disciples any less confused than us about this matter? Were they any less perplexed at how NON-common sensical Jesus pacifism seemed? Why did Jesus let those people continue to beat Him and mistreat Him? Why didn't Jesus recognize there was a point at which it just wasn't right to let them keep walking all over Him?

i'm sure physical violence/resistance justifiers would be tempted to say there's some key difference between what Jesus did and what we're supposed to do/allowed to do. But am i wrong in understanding that Peter clearly and explicitly pointed out that Jesus meant for this specific behavior on His part to be an example for how we ought to behave (1Peter 2:21-23)?

So again, just a simple question: Does the Bible authorize me, a Christian, to engage in any physical violence at all ever?