The part of that execution that libtard history textbooks have conveniently forgotten is that the Vietcong asshole losing his brains had just invaded the home of a South Vietnamese military officer (while he was not at home) and killed half a dozen members of his family. One girl survived hiding in a closet.
The officer's friends dragged the VC out of the house and the decision was made to get it done and over with. Technically that violated South Vietnamese law, but had they gone through the whole procedure of bringing him before a judge, he'd have spent a few months in the 'tiger cages' of Con Dao Island before his execution date.
The libs who parrot this whole episode as a war crime can't see that the man with the gun in this video did the VC terrorist a favor.