>They hate each other in a way most people probably cannot understand. Many would not pass up the opportunity to rid the world of what they see as the most evil

>They hate each other in a way most people probably cannot understand. Many would not pass up the opportunity to rid the world of what they see as the most evil upon its face unto the very last minute. That really isn't true, which is largely why the First World War was characterised by immobile trench warfare. A group of experienced and highly motivated soldiers were perfectly capable of breaking the lines and holding territory, as demonstrated by Stoßtruppen and Arditi, but most soldiers weren't experienced and highly motivated - they were barely-trained civilians who just wanted to go home in one piece. They might have occasionally fired a few shots over the barricades to show willing, they might have chosen to risk death in a charge over the lines rather than face certain death by firing squad, but they really didn't want to be fighting and certainly didn't want to risk death or live with the consequences of having killed. Snipers can achieve remarkable combat effectiveness, partly because of their marksmanship and fieldcraft skills but mainly because they're actually shooting to kill, due to an innate or acquired psychological difference from ordinary infantrymen. Most infantrymen weren't really trying to kill anyone, which is why the overwhelming majority of combat casualties were inflicted by artillery - it is psychologically far easier to fire an artillery piece at a grid coordinate than to fire a rifle at a human being. The burden of sustained combat or psychologically-informed training can increase the propensity of people to kill, but it's not a natural psychological state. Ordinary men under prolonged stress sometimes become hardened killers, but they're more likely to become disaffected and depressed. Modern military strategy is based on this reality - a small proportion of elite infantrymen at the tip of the spear, supported by vast numbers of men in support and indirect combat roles. Tanks, aircraft and drones provide firepower, but just as crucially they provide psychological distance from the act of killing. The significance of psychological distance is a crucial but often overlooked aspect of the Milgram experiments.