‘Doctrine’ consists of fundamental principles by which military forces guide coordinated actions in support of national objectives. It may include terms, tactics, techniques, and procedures, including standard operating procedures (SoPs). Military doctrine constitutes official advice, but requires judgment in application.

Policy is more changeable, if also directive, while doctrine is more enduring. Policies may change due to changes in short-term objectives, national leadership, political considerations, or for fiscal reasons. In the national sphere, policy may be expressed in such broad normative instruments as presidential executive orders. Within military operations, policy may be expressed not only as a means of pursuing objectives, but also in rules of engagement (RoEs). Normally, policies, orders and other directive instruments align with more foundational military doctrine.