This is literally what a lot of police training in the United States is. David Grossman's "killology" approach is extremely influential, and that's pretty much what the training is designed to do: convince you that, as a police officer, you're constantly at war with the citizens you're policing, and killing them is really no big deal because they're such dangerous enemy combatants.
Literally training yourself to be a sociopath.
This is literally what a lot of police training in the United States is. David Grossman's "killology" approach is extremely influential, and that's pretty much what the training is designed to do: convince you that, as a police officer, you're constantly at war with the citizens you're policing, and killing them is really no big deal because they're such dangerous enemy combatants.