The answer is: The Law of Land Warfare, Uniform Code of Military Justice, and Code of Conduct.
The answer may vary from country to country but on an international level the United Nations Charter also provides code of conducts on how modern armies should function in times of war.
These are important in order to provide a moral structure to an Army which can become, as evidenced in history, quite ruthless.
They don't teach it enough perhaps ?
Answer: Well, I feel as if Biden deserves to win. I feel the need for a new president, one that will keep things under control. And not riot his supports to attack the capitol.
Explanation:(My apologies if this offends. Just stating my honest opinion)