Yes, and no. The reasoning behind it may be morally justified, but war is never moral.
- War is a state of armed conflict between different nations or states or different groups within a nation or state.
War itself is not a good thing. It indicates that all rational dialogue between two or more parties has failed. War can, however, have byproducts that can lead to good things. Those byproducts usually come at great cost, financially and mortally.
You can justify why we go to war (self defense, etc.), but that (normally) places an inherent value on your life over that of another. Which means war is inherently wrong. The reasoning behind going to war is not always immoral, just the act of war itself. It is a fundamentally pathological behavior that simply demonstrates our lack of advancement beyond other animals regarding conflict resolution.
War can be justifiable to the point of defense, but war itself is not just.