The Joint Chiefs of Staff (JCS): A prominent United States-based governmental body, the JCS comprises the most senior uniformed leaders within the Department of Defense. Headquartered at the Pentagon in Arlington, Virginia, its primary mission is to advise the President, Secretary of Defense, and National Security Council on military matters. The JCS focuses on ensuring personnel readiness, policy, planning, and training for the US armed forces. Established formally by the National Security Act of 1947, it plays a significant advisory role in national defence policy and strategic direction, though it holds no operational command authority over combatant forces.