Having been a practicing Jehovah's Witness for 30 years, I had been exposed to their pacifist doctrine, which taught that Christians were not to enlist in armies or participate in warfare on any level. This doctrine was later modified somewhat to allow for non-military "alternative" service as a matter of conscience.
I had always thought of the JW doctrine as lofty. It was based on Bible verses such as Isaiah 2:4 and Matthew 26:52. The idea was that, if all people were Jehovah's Witnesses, carnal warfare would be eliminated. In fact, one anecdotal experience often related in JW talks about warfare was that of a JW who supposedly called at the door of someone who related that they had lost a son in battle. The JW supposedly said "if all people were Jehovah's Witnesses, your son would still be alive today".
But the fact is, not all people are Jehovah's Witnesses. And, though I bought into the lofty ideal behind this JW teaching, one thing bothered me: It was idealistic, but not entirely practical. For example, aggressive people and nations do exist. At times, such aggressors must be confronted. A foremost example is Adolf Hitler's Germany during World War II. Hitler turned Germany into an aggressor nation with global aspirations. In fact, Jehovah's Witnesses themselves were victims of that aggression, having been condemned to concentration camps along with Jews, Gypsies and others.
Interestingly, another anecdotal story often related by JW public speakers is that God may have used the Allied forces in WWII to free the Witnesses from the concentration camps, in much the same way that He supposedly used the Persian forces to free Israelites from captivity in Babylon in the 6th century BC. The question raised by that suppostion in my mind was 'if everyone was a pacifist, where would the deliverance have come from?'
Back to Hitler's Germany, from where would salvation have come if not for the Allied forces? What would the world be like had Hitler been left to pursue his goals unchecked? One thing is sure - religions like that of Jehovah's Witnesses would not enjoy freedom to practice their faith.
Indeed right up to the present time, aggressive nations and people (including terrorist groups) exist which at times must be confronted. To me, the Jehovah's Witnesses teaching, lofty as it was, failed to address this. Lately, I've been reading up on the Catholic doctrine of "Just War", which is explained here. The Catholic doctrine holds that, while there are Bible principles aimed to ensure peace, there are also principles which show that war may be, regrettably, necessary at times.
To me, the Catholic doctrine of Just War may better address the realities of the world we live in. If there is some drastic change in the future, such the second coming of Christ, then, yes, war should be a thing of the past. But for now, war is a sad reality, never to engaged in lightly or for the wrong reasons, but at times necessary nonetheless**.
http://http://www.catholic.com/library/Just_war_Doctrine_1.asp
** The viewpoint I am presenting is not a statement of support for the current war in Iraq. The Iraq War, in my opinion, is much more complex than that of WWII, in my mind anyway. I do not wish to address the differences at this time, though it should be noted that I am not totally against the current war either. However, I will say that the Persian Gulf War matches WWII a bit more closely, in my view.