War is an act of force which theoretically can have no limits. War tends towards the ultimate exertion of forces. Moderation in war is an absurdity. War is hell. In reply to Clausewitz and Sherman, war does have limits.
War is hell when people are forced to fight, when the limit of consent is breached.
In modern wars, the power of the State to wage war is such, that individuals can be coerced to fight, directly, through conscription, or subtly induced to volunteer through propaganda. The laws of war include restrictions on how war may be waged. These may vary with changing technological capacity. Basically combat should be between combatants. International Law recognises these principles, particularly in the form of the Geneva Conventions of 1949, and their additional Protocols, signed in 1977.