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.
He predicted that it would first happen in France
An island off the east coast of the United states of America,Ellis Island, was officially designated as the formal immigration entry point and gateway for immigrants mostly from Europe arriving to the east coast of the United States by the then President Benjamin Harrison in 1890. It today harbors the statue of liberty, a national monument.
