Why is illegal for CS gas (tear gas) to be used in warfare but countries can use it on their domestic population?

Question

Title.

In: 4

Answer 1

There is no why, other than, “We signed a treaty”. International law is, in reality, just a tissue of agreements that various coutries have agreed to abide by. When one country stops abiding by the treaty, the other signatories have one of two options: Do nothing, or go to war.

So, like any law, in any country, international treaties don’t have to make sense. For some reason it’s illegal for me to gas enemy troops with a chemical irritant, but I can bombard them with explosives that will blow them into bolognese.