MCO 3300.4A governs the Marine Corps Law of War Program, including law of war training and reporting requirements.
View MCO 3300.4A on armypubs.army.mil
MCO 3300.4A establishes entry-level, follow-on, specialized, and detailed training, including testing and realistic mission-oriented scenarios. It defines Reportable Incidents and sets requirements for reporting, investigating, and preserving evidence of alleged law of war violations.
Entry-level law of war training, as set forth in enclosure (2), will be provided to every newly accessing Marine, whether officer or enlisted, at Officer Candidates School or the Marine Corps Recruit Depots. (paragraph 4)
Training will be conducted as a formal part of the respective training curriculums and will include testing to ensure mastery of the material. (paragraph 4)
The "Core Principles" of the law of war are the following: (1) Military Necessity. (2) Unnecessary Suffering. (3) Discrimination/Distinction. (4) Proportionality. (paragraph 1)
Marines do not torture or kill enemy prisoners of war or detainees. Marines treat them humanely. (paragraph 1)
A Reportable Incident is a possible, suspected, or alleged violation of the law of war, for which there is credible information, or conduct during military operations other than war that would constitute a violation of the law of war if it occurred during an armed conflict. (paragraph 4)