Is there a "Just War" for Christians?

Recently I was asked in an email about a Christian serving as a chaplain in the military, and whether a chaplain could be in the military and be against war--not just the current war. The questions in the email went on to ask about the theory of a "just war." Here is what I said...

Dear......
Thanks for writing. First let me provide a link to a letter written to the President and signed by a number of evangelical leaders outlining the just war theory and how they apply to the current situation:

http://www.answers.com/topic/land-letter-1

Second, let me say that to be a military chaplain and do so with integrity cannot, in my view, be accomplished by a pacifist—that is, by one who rejects armed conflict as a legitimate means of national protection. In order to honestly, spiritually counsel servicemen and women when you believe that the undertaking to which they have committed themselves is immoral, you would have to tell them to resign, refuse to obey combat orders, or desert—none of which you could do and be faithful to your own loyalty to the service.

Third, I believe that a fair reading of the NT will point out a number of key points to help sort this out…
1. Jesus’s command to “turn the other cheek” had to do with personal dealings, not national conflicts. The ethics of the Sermon on the Mount are personal. If governments tried to follow them, they would fail to perform the functions for which God ordained government—namely the protection of societal peace and the punishment of evidoers—see Romans 13:1-7; 1 Peter 2:13-17; see also Prov. 24:21, 31:4-5 (there are many other passages that speak of the duties of human government, including carrying out the death penalty for murder in Genesis 9:6 and as a result of violating the commandment against murder in Exodus 20).
2. Romans 13:1-7 speaks of rulers “bearing the sword.” This refers to government’s legitimate power to punish, up to and including death, those who do evil. It also may infer military power.
3. Never does Jesus or any of the apostles who dealt with Roman soldiers call upon them to give up their career as sinful—in fact the first totally Gentile convert to Jesus was a Roman centurion (see Acts 10 for the story). Neither is there any NT statement repudiating soldiery. It is interesting that Paul even uses being a good soldier as an illustration of our devotion to Christ. He uses lots of illustrations (farmer, runner, boxer, family life) but never one that is morally reprehensible. When John the Baptist counseled soldiers, it was to behave properly, not to quit (see Luke 3)
4. Just war theory is based on this governmental power to protect society and to punish evildoers, and applying it to our dealings with nations.
5. Let me give you an example of how individual Christians fit into this picture. The Bible clearly states that murder is worthy of the death penalty. It is outlined in Genesis 9 and is one of the 10 commandments. Now, some would argue that Jesus teaches forgiveness, so we must forgive. On an individual basis, that is so, but it does not remove the consequences of sin, any more than asking God to forgive you for being promiscuous sexually will automatically remove any physical consequences that might have resulted, from STDs to pregnancy. But let’s assume we have a person in prison who is a serial killer who has raped and murdered children. He is unrepentant, and after conviction has been given the death penalty. You are a prison guard, and are assigned to the execution detail of this prisoner. In fact, you will be the one who actually pulls the switch to start the lethal injection that ends his life. If you do so, are you guilty of murder? The Bible’s answer is a resounding “NO!” First, you are not acting out of personal motives, but as a duly constituted governmental authority ordained by God. Second, the government is acting in obedience to God’s law in passing this judgment. Is this a serious responsibility? Yes. Is it sin? No.
6. Now, apply that principle to dealings between nations. If "Hitler, Jr." emerges in Canada and decides he should own Alaska and invades, should the U.S. protect its citizens, even if that means our military may kill Canada’s invading forces? This certainly fits a biblical definition of governmental authority acting appropriately to protect society. What if "Hitler, Jr.," in Canada, decides all French speakers are to be rounded up and shot? Should our government, which has both the power to intervene and some level of personal concern for innocent life, do anything to prevent the deaths of millions at little U.S. risk (after all it’s Canada we are talking about)? Many would argue that a moral government with means should use them to stop overt evil when such action does not endanger other important governmental responsibilities. This is where application of these principles gets less absolute and clear. The holocaust in Europe during WWII is an example where many nations that claimed "moral standing" refused to act to stop Hitler before he could commit the atrocities he did. U.S. and international refusal to accept Jewish refugees throughout WWII and even after is considered by many the abdication of our moral responsibility.

Well, I haven’t given you an answer, but I hope I have given you some things to think about.