In War: out of uniform == can be shot as a spy?

Can soldiers summarily execute enemy civilians legally?

Depends on whether the country they are from signed the Geneva Convention Treaty. If not then legality really has no meaning. I mean are they going to be subject to the laws of the country they invaded? I guess if they loose the war they could. Or if their own millitary prohibits it. But generally the various treaties prohibit the killing of unarmed non-combatants, but like I said that does not apply to countries who are not signitories of the treaty. Also there is the issue of enforcement, see Sudan.

Under the conventions, no. Civilians taking up arms against enemy soldiers have given up their protected status and they can be killed in combat without it being a war crime - but there’s absolutely no provision for on-the-spot execution-style killings of any sort of captive.

Resistance forces fighting enemy soldiers must have a recognised chain of command and wear something that identifies them as a combatent even if its just an arm band.

I think technically a civilian who attempts to kill a soldier can be shot on the spot though thats just my hunch but in practice its unlikely to happen in this day and age.

For surrendering soldiers it is allowed by the rules of war to shoot them if they are attempting an “instantaneous” surrender,that is they are shooting at you one instant and then suddenly throw down their weapon the next in a hot firefight.

Does the “not entail any violence against life or limb” mean that the POW camp guards are off-limits? If Lebeau strangles Schultz on his way out of camp to Dusseldorf one night, can/will he be tried for murder?

That’s exactly my point. A guy without a uniform wandering around taking notes can’t be shot summarily, any more than a random civilian can be shot summarily. Of course, soldiers can and do kill civilians during military operations, all legally under the Geneva Conventions. But you can’t just take a civilian prisoner, shout “He’s a spy!” and shoot him right there. You can take a civilian prisoner and hand him over to the MPs, and a tribunal can determine the fate of that civilian. If the civilian was not part of an organized force but was shooting at your soldiers, that civilian could face murder charges, and therefore could face the death penalty if your laws allowed the death penalty.

The revelation that an person is a spy does not entitle any soldier to summarily execute that person. Of course, on the real battlefield soldiers sometimes do summarily execute prisoners, or surrendering enemy soldiers, but they violate the Geneva Conventions when they do…that is, they commit murder. Now, since this is a battlefield the likelihood of being prosecuted for these murders is a lot lower than if they shot their neighbor back home.

Of course, this only applies to prisoners, or people attempting to surrender. If a civilian is shooting at you, you can legally shoot back, just as you could against enemy soldiers. If that civilian stops shooting at you and starts running away, you can still keep shooting. It’s only when you take the civilian prisoner that it matters. An enemy soldier POW can’t be tried for murder just because he shot a dozen of you. An enemy civilian prisoner can.

Irregular combatants, such as civilian guerillas or soldiers out of uniform for the purposes of deception, can be (but might not be) considered francs-tireurs and thus are liable to execution upon capture according to the laws of war, at least following WWII.

The Wilhelm List trial in Nuremburg held that “We are obliged to hold that such guerrillas were francs tireurs who, upon capture, could be subjected to the death penalty. Consequently, no criminal responsibility attaches to the defendant List because of the execution of captured partisans…”

In short, it was not a war crime for List to have executed captured prisoners who did not meet the status of POW. Captured soldiers under arms would (should) not be treated this way. But guerillas and suchlike can (and have) been.

Wiki for the Hostages Trial (that concerned List): Hostages Trial - Wikipedia

Wiki for the Laws of War: Law of war - Wikipedia