I havent looked into this, its primarily derived from my readings into the iraq war and vietnam. I appreciate your response as well.

If I seemed hostile, I do apologize. I was politically aware during the GWOT, and while much more conservative at the time, even at that point in my political development, justifications for violations of the laws of war... rankled. I'm somewhat 'on-guard' about such topics for that reason.

How would a country go about fighting a seperate country when they wont id their combatants? I, just logically, cant see a way beyond “everyones a combatant/no one is a conbatant”

Is it really as simple as “if theyre not wearing combat gear, you cant shoot them until theyve shot at you”? That seems… absurd, when you know the enemy is mixed into the civilian populace.

It depends on the exact goals of the 'organized' force.

Forces attempting to preserve local support (or domestic PR) typically go through pretty thorough identification processes for enemy combatants who do not clearly ID themselves. These are generally covered by what are known as 'RoE' - 'Rules of Engagement' - which are distributed to troops in combat zones outlining when they are allowed to fire on a target. In Afghanistan, for example, during much of the low-intensity conflict, when it was uncertain whether rando militiamen in the mountains were friend or foe, RoE could be very strict, requiring soldiers to not fire on a target even firing on them until they were clearly ID'd. While this may seem absurd, the last thing an occupying power wants is to end up icing allied fighters just because they're dumbass trigger-happy locals - that would be a quick way to convert allied fighters to enemy fighters.

In the broadest sense, though, the obligation is just for a military to make a reasonable attempt to differentiate between civilians and non-combatants - ie indiscriminately shelling a town for the crime of being a town in enemy territory would not pass muster, but "There are armed foot mobiles spotted that aren't our's" would often be enough for a targeted strike.

The capabilities of the force for precision and identification are also taken into account. If you're dropping bombs with gear that has a 1-mile radius of accuracy, not launched until hours after the first intel reports of enemy activity come in... well, first, update that WW2 fucking equipment, but second, you aren't going to be held to high standards for whether your bomb falls directly on the head of enemy troops. On the other hand, if you've got a remote-guided hellfire missile that can choose which door of a moving car to hit, and you gib a bunch of civilians with it instead, you're gonna have to have a pretty clear answer beyond "They were in the AO" for why you didn't have a clear ID on enemy combatants before making the decision to strike.