Department of Defense Directive 5100.01
Functions of the Department of Defense and Its Major Components

Within the Office of the Secretary Defense (OSD) the Director, Administration and Management,  Directorate for Organizational & Management Planning is responsible for maintaining and updating Department of Defense (DoD) Directive (DoDD) 5100.01, Functions of the Department of Defense and Its Major Components.  The Directive describes the organizational relationships within the Department, and is the foundational issuance for delineating the major functions of the Department.  The latest version, signed by Secretary Gates in December 2010, is the first major re-write since 1987, supports DoD strategic processes, and aligns with the overall goals and priorities of the Department.    

Most Recent Update – The current DoDD 5100.01 was affirmed through formal coordination across the Department in 2009 and 2010, culminating in its endorsement by the Joint Chiefs of Staff and the Secretaries of the Military Departments in summer 2010.  Some of the significant changes from previous iterations of DoDD 5100.01 incorporated in this version include:

• New and expanded sections:  Reflecting input from the Quadrennial Roles and Missions Review (QRM) in 2008 and formal coordination, the Military Department sections are extensively revised and the Directive includes new sections for the U.S. Special Operations Command (USSOCOM), the U.S. Coast Guard, and the National Guard Bureau (NGB).  Further, the document is now formatted with enclosures, including new enclosures delineating the functions of OSD and the Office of the Inspector General of the Department of Defense .  Similarly, the Defense Agency and DoD Field Activity enclosures are expanded. 

• USSOCOM.  Through QRM input, DoDD 5100.01 now describes USSOCOM as a unique combatant command and details its functions, some of which are similar to those of the Military Departments.  However, nothing in the Directive implies that USSOCOM is a Military Service, and its language remains consistent with U.S. Code.  For example, DoDD 5100.01 now describes USSOCOM unique combatant command functions in the area of personnel management.

• Functions of the Military Departments.  These sections are now up to date, reflecting the evolving roles and missions of each Military Department and Military Service.  Common functions are aggregated and the lead-in paragraph for each is enhanced to reflect the composition, principal domain, role, functions, and force projection mode for each.

• PSYOPS to MISO.  The language in the Directive incorporates Department-wide replacement of the term “psychological operations (PSYOPS)” with “military information support operations (MISO).”

Overall, these and other changes in the 2010 revision reflect the enhanced role of non-Service Components (e.g., the NGB and SOCOM) and the blurring of roles, missions, and functions between the  Services.  Likewise, the new iteration of DoDD 5100.01 provides the current organizational construct within the Department (notwithstanding the disestablishment of U.S. Joint Forces Command and the Business Transformation Agency, nor the elevation of the Chief of the National Guard Bureau to the Joint Chiefs of Staff), and, with those exceptions, presents the current functions of the Department and its major Components.

White Paper: Evolution of Department of Defense Directive 5100.1
Functions of the Department of Defense and Its Major Components

This paper examines the evolution of Department of Defense Directive (DoDD) 5100.1, Functions of the Department of Defense and Its Major Components. It reviews the post-World War II defense reform debates that resulted in issuance of the first DoDD 5100.1, highlights key modifications made to the Directive over time, and identifies the stakeholders behind each revision. Because U.S. military roles and missions naturally feed into, and often
dictate, the functions described in the Directive, this paper also includes a discussion of roles and missions as they have changed over time. Thus, this paper can serve as a valuable reference regarding the history of the Department of Defense, the evolution of its roles and missions, and related policy discussions.

Click here to view the White Paper.