A military operation plan (commonly called a war plan before World War II) is a formal plan for military armed forces, their military organizations and units to conduct operations, as drawn up by commanders within the combat operations process in achieving objectives before or during a conflict.
The United States developed a famous color-coded set of war plans in the early 20th century; see United States color-coded war plans.
[2] An OPLAN is developed by the Combatant Commander (CCDR) of a Unified Combatant Command in response to actual or potential situations for which military operations may be required.
An OPLAN is executed when the commander issues an operations order (OPORD), or when the Chairman of the Joint Chiefs of Staff (CJCS) issues an execute order (EXORD) at the direction of the United States Secretary of Defense (Secdef) to implement a decision by the President to initiate military operations.
[3] In North Atlantic Treaty Organization (NATO) the successful planning of multinational military operations requires common doctrine.