With the ongoing tension arising because of the bellicose provocations from North Korea, many believers are pondering whether it would be moral for the USA to initiate a pre-emptive strike. The objective of course would be to protect American lives in the same way it would be moral for a police officer to shoot a person armed with a gun about to kill an innocent person. Of course there are many things to consider as a believer and as a rational human being.

First of all, we have to consider if there are any options that do not involve military conflict.
Second, as believers we have to consider the fact that there are millions of praying Christians in harm’s way in South Korea, Japan, and other nations within striking distance of the missiles of North Korea — not to mention the unnumbered among the persecuted church in North Korea that our military strike will annihilate.

Many centuries ago, the influential church father, St. Augustine (the bishop of Hippo in North Africa) wrestled with the question of armed conflict when he proposed what he called “the just war” theory.
To summarize, Augustine said that some wars are just in the eyes of God and some are unjust. To opine, a just war is one that arises out of a motive to save and/or to protect human life, and an unjust war is predicated upon wrong motives such as greed, conquest, and exploitation of human life (such as the forceful capture of humans for the slave trade industry).

In the New Testament we read about how God has entrusted civil authorities with the sword to punish evil doers (Romans 13:1-7).
Although the context in that passage is primarily concerned with keeping domestic peace and civility — you can possibly extrapolate it in principle to also include the civic duty of magistrates to protect their people from an enemy attack within their nation or from another nation. Old Testament examples also abound regarding how God was with certain nations, including Israel, and granted them military victory for a righteous cause.

(The Israeli conquest and subsequent genocide of many peoples living in the seven nations of Canaan — as found in the book of Joshua — fits in a different category than our present conceptual understanding of a “Just War,” since it fits more into the sovereign plan of God to use Israel to mete out divine punishment to peoples fully given over to sinful abominations worthy of death in God’s eyes — as He subtly prophesied to Abraham as recorded in Genesis 15:16 — something too deep and controversial to attempt to unpack in this brief article.)

Believers who attempt to promote pacifism by citing passages such as Jesus admonition not to resist evil and to turn the other cheek (Matthew 5:39) as well as the admonition from Paul not to repay evil for evil (Romans 12:17-21) fail to understand that the context in these verses has to do with an admonition against individual retribution — it has nothing to do with prohibiting civic authorities from using the sword to punish evil doers or to protect human life (which would contradict Romans 13:1-7).
Of course, the greatest recourse we have as believers is to pray for our political leaders so that we may lead a peaceful and quiet life so the gospel can go forth uninterrupted (read 1 Timothy 2:1-4).

Military conflict and war hinders the spread of the gospel because it pits one nation against another (nationalism) making it difficult for Christians of opposing sides to cross pollinate and evangelize — as well as the fact that it is dangerous and almost impossible for church mission to function in war zones.

In my opinion, there are at times just wars with ethical objectives (EG think of the US Civil War to free the American slaves; think of WW II when we fought heroically against the demonic forces of Nazi socialism under Hitler; think of our current fight against ISIS and terrorism).
 Unless there is divine intervention — as mentioned before — there seems to be few if any good options if the USA goes to war against North Korea, but if attacked, and/or if intel tells us a pre-emptive strike is our only option to save the maximum amount of human life, then I pray our military response fits under the rubric of “A Just War.”