Rethinking Military Roles and Missions in a New Administration

This piece is part of the CSIS International Security Program’s Transition46 series on Defense360.

Whether it wants to or not, the Biden administration will be forced to grapple with questions over how roles and missions are allocated among the military services. Rather than ignoring the issue or handling roles and missions disputes in a piecemeal manner that reacts to problems as they arise, the Department of Defense (DoD) should begin a narrowly scoped strategic review of roles and missions as part of the upcoming national defense strategy review. This roles and missions review should focus on eliminating gaps, redundancies, and areas of ambiguity among the services created specifically by the establishment of the United States Space Force, advancements in technologies such as artificial intelligence and hypersonic weapons, and the emergence of new and expanded military missions. In particular, DoD should consider transferring the land-based leg of the nuclear triad to the Army and designating a lead service for the development of an overall architecture and interface standards for Joint All Domain Command and Control (JADC2).

Q1: What are military roles and missions, and why are they important?

A1: Military “roles” are generally defined as the “broad and enduring purposes of each service” and are loosely defined in law. The term “missions” generally means the specific tasks and functions each service undertakes to carry out its roles. Historically, roles and missions have also been called military functions, which is perhaps a more succinct description of what the phrase is intended to encompass.

The clear assignment of roles and missions among the military services is necessary for effective strategy development and the efficient fielding of forces. Without clear allocation of roles and missions, the U.S. military risks allowing gaps in capabilities to emerge where no service claims responsibility, or it could find itself wasting precious resources on unintended redundancies among the services.

Q2: What is the history of military roles and missions that led to the Key West Agreement in 1948?

A2: Prior to World War II, the allocation of roles and missions among the military services was relatively straightforward. The Army was responsible for operations on land, and the Navy was responsible for operations at sea. It was not until the widespread use of land and carrier-based aircraft that the roles and missions of the services began to overlap in significant and enduring ways.

The National Security Act of 1947 created the Air Force and unified the services in a single organization under the secretary of defense. While some believed at the time that this would settle long-standing differences among the services about their respective functions in the joint force, these expectations proved to be overly optimistic. The Navy set out to develop nuclear-armed bombers of its own in the months after the Act passed, which caused deep concern among Air Force leaders that the Navy was infringing on one of its primary functions—strategic bombing.

As an ad hoc committee of the Joint Chiefs of Staff noted in a memo to Defense Secretary James Forrestal in January 1948, constraints on “money, manpower, and industrial capacity” meant that clear and unambiguous guidance was needed on the roles and missions for each of the services. This set off a chain of events which resulted in Secretary Forrestal convening the Joint Chiefs of Staff at the Key West Naval Base in March 1948 to resolve lingering disagreements over roles and missions. After days of discussions in Key West and continuing discussions in Washington, D.C., Secretary Forrestal issued the final version of a document that became known as the Key West Agreement.

The Key West Agreement was needed in 1948 due to the confluence of three key changes going on in the military at that time: the establishment of new organizations, advances in new technologies, and the creation of new military missions. The separation of the Air Force from the Army—and the growing role of air power in military operations—created fundamental questions over which air capabilities each service would keep, and which would be centralized in the Air Force. At the same time, the post-war environment led to fast-paced innovation in military technologies, such as increasingly powerful and miniaturized nuclear weapons, jet-powered aircraft, long-range ballistic missiles, and supercarriers. These technologies made it possible to perform existing military missions in new ways, and they enabled new and expanded military missions.

Q3: Are we at another inflection point like 1948, in which a roles and missions review is needed?

A3: More than seven decades after the Key West Agreement was reached, the military has arguably reached a similar inflection point. The gradual transfer of organizations and personnel to the Space Force has highlighted the need to establish better boundaries and definitions to delineate between the space capabilities and space operators that belong in the Space Force, and the residual space expertise that should remain in the other services. While the policy document that allocates roles and missions—Department of Defense Directive 5100.01: Functions of the Department of Defense and Its Major Components—was updated after the creation of the Space Force, it now lists the Army, Navy, Air Force, and Space Force as separate providers of space forces responsible for conducting space operations. This overlap is likely to lead to redundancies and the inefficient use of resources. Moreover, the last thing Congress intended when creating the Space Force was to end up with four different space forces.

Similarly, the rapid pace of technological developments in hypersonic weapons, artificial intelligence, cyber capabilities, remotely operated systems, and autonomous systems is enabling each of the services to reimagine how they operate and the types of forces they need. The Navy, for example, is planning to shift significant resources into uncrewed ships and submarines to expand the fleet and distribute operations over a larger number and variety of assets. Moreover, the past two decades of wars in Iraq and Afghanistan highlighted how new and expanded military missions can be enabled by new technologies, such as the ability to conduct continuous wide area surveillance and strike operations using long-endurance, remotely piloted aircraft—something that is not feasible with crewed aircraft.

Q4: How comprehensive does a new roles and missions review need to be?

A4: It is not likely that the new administration will embark on a full roles and missions review soon after taking office, but it will be forced to address gaps and overlaps in roles and missions one way or another. The default approach is to do this in a piecemeal and reactive manner, attempting to resolve issues individually as they become pressing problems. A more strategic approach, however, would be to address questions about the services’ respective roles and missions in a more holistic way before they become problems for DoD.

A strategically scoped roles and missions review does not need to be a comprehensive review that rehashes long-standing divisions of responsibilities among the services. A comprehensive review would likely create new controversies and distract attention from the most pressing questions that need to be resolved. Instead, a roles and missions review should be narrowly scoped to focus on the gaps, overlaps, and areas of ambiguity among the services that stem specifically from (1) the creation of the Space Force, (2) advances in new technologies, (3) changes in current military missions since Key West, and (4) the emergence of new mission areas that are strategically important to DoD. A natural vehicle through which DoD could conduct a strategic review of roles and missions would be the next National Defense Strategy, which under current law must include “the priority missions of the Department of Defense” and the “roles and missions of the armed forces to carry out” said priority missions.

Q5: Who should be involved in a new roles and missions review?

A5: Several lessons can be learned from the process that led to the Key West Agreement and subsequent efforts to revise roles and missions. One lesson is that leaving the service chiefs to reach a consensus on their own—which is what Secretary Forrestal tried at first—is not likely to be productive. It ultimately required direct intervention by the defense secretary to forge an agreement—and even then, the service chiefs never fully committed to the agreement. While the Joint Chiefs of Staff is a necessary participant in a roles and missions review, history suggests that it should not be tasked to lead such a review.

Another lesson from Key West is that a memorandum from the secretary of defense—which is the form the agreement ultimately took—may not be sufficient to establish and enforce roles and missions. While the Key West Agreement is often referenced in debates, it does not have the same binding power over the services that an executive order or statute would have. The services can push the boundaries of the Key West Agreement and its current instantiation in DoD Directive 5100.01 because these documents are only consequential insofar as the defense secretary is willing to enforce them in program decisions. Moreover, a higher level of authority, such as an executive order, may be necessary because some of the roles and missions that need clarifying today extend beyond DoD. For example, a roles and missions discussion for space should include the Space Force and the intelligence community (namely the National Reconnaissance Office). Similarly, cyber roles and missions encompass each of the services, U.S. Cyber Command, and the National Security Agency.

Ultimately, any significant reallocation of roles and missions among the services will require strong leadership from the secretary of defense, the backing of the White House, and buy-in from Congress. Congressional involvement in the process is critical because it can block or mandate changes in roles and missions. While Congress has generally been willing to defer implementation of these matters to the military, it remains a key stakeholder in the outcomes and must be consulted and included in the process.

Q6: What changes in roles and missions should the Biden administration consider?

A6: While there are many missions that could potentially be addressed in a new roles and missions review, two stand out as particularly important for consideration given recent organizational changes, advances in military technology, and the most recent National Defense Strategy.

Move Intercontinental Ballistic Missiles (ICBMs) to the Army

The separation of the Space Force from the Air Force makes the ICBM enterprise more isolated and unsustainable than ever. As a 2014 study noted, the ICBM career field has long suffered from low morale, perverse career incentives, and insufficient promotion opportunities—all of which have made it a less desirable career option within the Air Force. In 2013, for example, no Reserve Officer Training Corps (ROTC) cadets listed the ICBM career field (13N) in their top three choices. After years of bonuses, these figures have improved somewhat, but the ICBM career field remains in an untenable position within the Air Force. The missileer career field became more difficult to sustain as the size of the ICBM force declined from 450 to 400 operational missiles over the past few years, further reducing opportunities to gain experience and advance to higher ranks.

Some have suggested moving the ICBM enterprise to the Space Force, but a more natural fit and cost-effective option may actually be to move it into the Army. The only other silo-based weapon system in the U.S. military is the Ground-based Midcourse Defense (GMD) system, which is operated by the Army in Fort Greely, Alaska, and Vandenberg Air Force Base in California. Both ICBMs and GMD must remain on alert at all times and are critical components of nuclear deterrence. The Army also operates a variety of shorter-range conventional missile forces, and the ICBM career field could become part of the broader field artillery military occupation specialty (MOS 13) or air defense (MOS 14) career fields within the Army. This would give ICBM crew members more career flexibility and opportunities for advancement, and it could make ICBM duty a more coveted assignment in one’s career because of the extra responsibility and diligence required of nuclear forces. For Army artillery and air defense personnel, assignment to ICBM duty would offer a break from being at risk for deployment. Of course, the ICBM enterprise includes more than just the missileers—it also includes the ground forces that maintain security of the missile silos and control facilities, and the helicopter squadrons that transport ICBM crews and security forces around the missile fields. In this respect, the Army may also be a better home for ICBMs because the Army already has forces that specialize in site security, and it operates a variety of helicopter units. Moving the ICBM enterprise to the Army would relieve the Air Force from having to maintain separate helicopter pilot training and maintenance lines, which could be folded into the larger Army rotary-wing aviation structure.

Another advantage of moving ICBMs to the Army is that it would give each of the military departments a leg of the nuclear triad. Concentrating two legs of the triad in the Air Force is projected to strain the service’s budget as both are due for modernization over the coming decades. Moving ICBMs to the Army, along with existing modernization programs and funding, would more equitably allocate the responsibility and budgetary burden for maintaining nuclear forces according to each service’s respective domain.

Assign a Lead Service for Joint All Domain Command and Control (JADC2)

While joint operations across domains are not new, it is increasingly important for the U.S. military to maintain its power projection capabilities in the future threat environment. A key enabler in joint operations—and a critical deficiency in some weapon systems—is the ability to share data fluidly across ground, maritime, airborne, and orbiting platforms. The capability to share a common picture of the battlespace and make joint decisions has become known as Joint All Domain Command and Control, or JADC2. What is new in this concept is that many of these links will be machine to machine. When information can be shared at a machine level in near real time, it enables decisions to be made at a speed that outpaces the decision loop of adversaries. JADC2 is not a single acquisition program, nor is it the responsibility of any one service. It is envisioned as a meshed network of sensors, communication links, and data processing elements spread across platforms in all domains. While the Air Force has initially taken the lead in advancing the concept, it cannot be truly “joint” or “all-domain” unless the other services follow its lead and accept certain requirements on their platforms, such as security standards and communications protocols.

JADC2 is an example where emerging technology, threats, and strategy have created a mission area that does not neatly fit into any one service. A lead service needs to be assigned to design the overall network architecture, protocols, and standards for JADC2. While DoD Directive 5100.01 assigns the Joint Staff responsibility to “assess joint military requirements for command, control, and communications; recommend improvements; and provide guidance on aspects that relate to the conduct of joint operations,” the Joint Staff does not have the expertise required to architect the overall system of systems and develop the technical interface requirements for connecting to this architecture. In its attempts to build consensus for its approach to JADC2, the Air Force reached a temporary agreement to collaborate with the Army. But this agreement only lasts until September 30, 2022, and the Navy has not agreed to be part of this effort. Leaving the services to pursue their own approaches to JADC2 or engage in ad hoc partnerships is a recipe for failure. DoD needs to designate lead service for JADC2 if it is serious about building a truly joint architecture and achieving the operational benefits it can provide.

Once a lead service is designated, DoD can implement this decision by creating a Joint Program Executive Office (JPEO) for JADC2 and assigning the lead service to run the JPEO with representation from the other services and the Office of the Under Secretary of Defense for Research and Engineering. The Air Force can make a compelling case for being the lead service for JADC2 because it has made the most progress in this mission area to date, including its early efforts in the Advanced Battle Management System (ABMS) program. However, the Space Force may also be a good lead for JADC2 (and to take over the Air Force’s ABMS program) because nearly all the nodes in the future JADC2 network will likely reside in space, run through space, or be dependent on space-based capabilities.

Todd Harrison is the director of Defense Budget Analysis and director of the Aerospace Security Project at the Center for Strategic and International Studies in Washington, D.C.

Critical Questions is produced by the Center for Strategic and International Studies (CSIS), a private, tax-exempt institution focusing on international public policy issues. Its research is nonpartisan and nonproprietary. CSIS does not take specific policy positions. Accordingly, all views, positions, and conclusions expressed in this publication should be understood to be solely those of the author(s).

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Todd Harrison

Todd Harrison

Former Senior Associate (Non-resident), Aerospace Security Project and Defense Budget Analysis