During the Korean War in the early 1950s, the Chinese Army and North Korean Army captured some American military men. These American prisoners then faced a deadly new enemy, the Eastern World's POW environment.
For the American prisoners, brutal torture, random genocide, lack of food, absence of medical aid, and subhuman treatment became a daily way of life. Many of the Americans found that their training had not prepared them for this new battlefield.
After the war the American armed forces jointly developed a Code of Conduct. The President of the United States approved this written code in 1955. The six articles of the code create a comprehensive guide for all American military forces in time of war, and in time of peace. The articles of the code embrace (1) general statements of dedication to the United States and to the cause of freedom, (2) conduct on the battlefield, and (3) conduct as a prisoner of war.
The new Code of Conduct is not a part of the Uniform Code of Military Justice (UCMJ). Instead, the Code of Conduct is a personal conduct mandate for members of the American armed forces throughout the world. (excerpt from Warrior Culture of the U.S. Marines, copyright 2001 Marion F. Sturkey)