Army Doctrine Reference Publication (ADRP) 3-28 builds on the doctrinal foundation established in Army Doctrine Publication (ADP) 3-28 for the Army's contribution to defense support of civil authorities (DSCA). ADRP 3-28 explains how the Army, including all Components, conducts DSCA missions and National Guard civil support missions as part of unified land operations. ADRP 3-28 focuses on achieving unity of effort among the Army battalions, brigades, division headquarters, and Army Service component commands conducting DSCA with support from the generating force and in cooperation with joint and interagency partners. The principal audience for ADRP 3-28 is all members of the profession of arms. Commanders and staffs of Army headquarters serving as joint task force headquarters should also refer to applicable joint doctrine concerning the range of military operations and joint forces. Trainers and educators throughout the Army will also use this publication. United States Pacific Command and United States Northern Command conduct DSCA within their respective areas of responsibility. Users in United States Pacific Command should refer to theater plans and procedures for DSCA. Commanders, staffs, and subordinates conducting DSCA their decisions and actions comply with applicable U.S. and state laws and regulations. Commanders at all levels ensure their Soldiers operate in accordance with the rules for the use of force (see Joint Publication JP] 3-28.) They use interorganizational coordination processes discussed in JP 3-08, chapter 3, and the National Incident Management System and National Response Framework. ADRP 3-28 uses joint terms where applicable. Selected joint and Army terms and definitions appear in both the glossary and the text. For definitions shown in the text, the term is italicized and the number of the proponent publication follows the definition. ADRP 3-28 is not the proponent publication for any Army terms. In addition to military terms, this ADRP uses standard terminology and principles from the National Incident Management System and the National Response Framework. ADRP 3-28 applies to the Active Army, Army National Guard/Army National Guard of the United States, and United States Army Reserve, with four exceptions. First, Army National Guard missions conducted in state active duty status as National Guard civil support fall outside the definition of DSCA. Second, ADRP 3-28 does not apply to Army organizations conducting domestic counterterrorism operations. Third, ADRP 3-28 does not apply to military activities conducted wholly within any military installation in the United States. Finally, it does not apply to the United States Army Corps of Engineers although it plays a significant role in DSCA. Moreover, any mention of the National Guard refers to Army National Guard unless otherwise noted. The National Guard does not include any state defense force or equivalent that is not part of a state's Army National Guard. The proponent of ADRP 3-28 is the United States Army Combined Arms Center. The preparing agency is the Combined Arms Doctrine Directorate, United States Army Combined Arms Center.