Among the many issues the framers of the Constitution weighed at the Constitutional Convention of 1787 were the future size and role of the military. In the simplest sense, there were two camps: those who wanted a strong government and a standing army to protect the nation, and those who feared that a strong military could become the instrument of a free nation’s own destruction. Feelings ran deep, and there were battles both in framing the document and in its ratification.

In the end, the Constitution’s military clauses were a series of checks and balances. Congress held the purse strings and reserved the power to raise and support armies and to declare war. Military command, however, resided in the executive branch, with the president as commander in chief. The one overriding concept was that of civilian control of the military.

The existing secretary at war became the secretary of war, the primary military assistant to the president, and remained so for the next nine years. In April 1798, the Department of the Navy was created, and along with it the secretary of the navy. The secretary of war was in essence secretary of the army, and both services advised the president, who remained the sole arbiter of any disputes between the two. There were more than a few disputes, and efforts to unify planning and command in peace and war were never completely successful.

Following the Civil War, failings were analyzed, studies conducted, proposals made, and bills presented to Congress urging better coordination between the services. The Joint Army and Navy Board was created in 1903, composed of members of each service and intended to plan joint operations and solve the problems of cooperation between the services. However, it lacked the authority to back up its recommendations. It survived both world wars, but was dissolved in 1947.

The United States’ entrance into World War II changed everything. Just as the Pentagon provided a single headquarters building for all branches of the military to replace the many scattered buildings formerly housing various departments of the armed forces, the demands of total war made apparent the need to bring together each of the armed forces into a command structure forming a coherent whole. Meeting the demands of the war, the Joint Chiefs of Staff was formed to work with its British counterpart in planning combined operations against the Axis powers. Although it was not always completely successful in carrying out its mission, it did prove the advantages and even necessity of joint planning. Joint and combined operations played a crucial part in the Allied victory, and their success pointed the way toward the future. Tremendous advances in technology had also fused the elements of sea, air, and land battles together and made them interdependent, though this might not have been so readily apparent to the services, each of which had excelled in its own role.

In the postwar aftermath, what should have been an atmosphere of celebration was not, instead devolving into interservice rivalry and infighting over diminishing funds. After the sacrifices of rationing and the curtailment of spending on civilian goods and enterprises during the war, the public clamored for military budget cuts, and the armed forces struggled over their roles in a vastly changed world. The advent of the atomic bomb and primitive guided missiles caused some critics to call into question the need for conventional forces of any sort. From the perspective of the armed forces, talk of reorganization meant they were fighting not only for scarce funds, but for their continued existence. In addition to these problems, the president faced the rise of the Soviet Union and the United States’ position as the preeminent world power, leaving him with too many decisions to make about national policy without a formalized command and planning structure in place. It was simply too much for one man to oversee by himself.

With the CIA as its intelligence arm, the NSC was formed specifically as a civilian body to oversee the security of the United States in broad terms. The NSC took into account foreign, domestic, and military issues, and coordinated the military and civilian agencies of the government in national security matters.

There was a great deal of debate about how to reorganize. Although the Joint Chiefs of Staff formed during the war provided a partial model, there were other questions to be settled about the roles of the civilian and military leadership and the shape the structure of national security should take in the postwar world. The one main division was between those who thought a complete reorganization should take place, to create a new, completely unified department, and those who thought the organization as it stood simply needed to be modified by creating another level of management at the top to better coordinate everything. When the act took its final form, the principle of civilian control of the military remained, although its implementation had changed.

The National Security Act of 1947 created the National Military Establishment, laying the foundation of what was later named the Department of Defense. The act formalized the structure of the Joint Chiefs of Staff and made it the highest ranking military advisory group, comprising members of the Army, Navy (including the Marine Corps) and the newly created U.S. Air Force. In addition to the Air Force, the act created the National Security Council (NSC) and the Central Intelligence Agency (CIA).

With the CIA as its intelligence arm, the NSC was formed specifically as a civilian body to oversee the security of the United States in broad terms. The NSC took into account foreign, domestic, and military issues, and coordinated the military and civilian agencies of the government in national security matters.

The system has worked remarkably well, though it has seen a few changes over the years. The most significant was the Goldwater-Nichols Defense Reorganization Act of 1986, which enhanced the powers of the chairman of the Joint Chiefs of Staff and brought the long-held goal of jointness a giant step closer.

Perhaps more importantly, the act created the Office of the Secretary of Defense. The secretary of defense combined the offices of the secretary of war and secretary of the navy as principal defense policy advisers to the president, exercising authority over the entire Department of Defense. He also controlled and directed the national security policy of the nation. Under the authority of the president, the secretary of defense developed national defense policy, strategy, and the defense budget, and became the civilian leader who guided the military and represented it to Congress, the public, the media, and other nations.

Although the three service secretaries were reduced to sub-Cabinet-level positions soon after the creation of the act, ceding most of their responsibilities and authority to the new Secretary of Defense, they remained in command of each of the military departments. Thus, they carried on the philosophy of civilian leadership of the armed forces, and remain responsible for organizing, training, supplying, and equipping forces for assignment to the Unified Combatant Commands, according to the Organization and Functions Guidebook of the Department of Defense (DOD). The DOD also includes four intelligence agencies:

• Defense Intelligence Agency (DIA)
• National Security Agency (NSA)
• National Reconnaissance Office (NRO)
• National Geospatial-Intelligence Agency (NGA)Other agencies under the DOD include:
• Defense Advanced Research Projects Agency (DARPA)
• Defense Commissary Agency (DeCA)
• Defense Contract Management Agency (DCMA)
• Defense Finance and Accounting Service (DFAS)
• Defense Health Agency (DHA)
• TRICARE Management Activity (TCMA)
• Defense Information Systems Agency (DISA)
• Defense Legal Services Agency (DLSA)
• Defense Logistics Agency (DLA)
• Defense Media Activity (DMA)
• Defense Security Cooperation Agency (DSCA)
• Defense Security Service (DSS)
• Defense Technical Information Center (DTIC)
• Defense Threat Reduction Agency (DTRA)
• Defense POW/MIA Accounting Agency (DPAA)
• Missile Defense Agency (MDA)
• Washington Headquarters Services (WHS)
• National Guard Bureau (NGB)
• Army National Guard (ARNG)
• Air National Guard (ANG)
• United States Military Entrance Processing
• Command (USMEPCOM)
• Central Security Service (CSS)
• National Assessment Group (NAG)

The system has worked remarkably well, though it has seen a few changes over the years. The most significant was the Goldwater-Nichols Defense Reorganization Act of 1986, which enhanced the powers of the chairman of the Joint Chiefs of Staff and brought the long-held goal of jointness a giant step closer. The following year the Nunn-Cohen Amendment formed U.S. Special Operations Command (USSOCOM) as a separate command, which proved prescient in the first years of the 21st century, when asymmetrical warfare against terrorist organizations and insurgencies needed just such a command.

When the Pentagon was completed some 75 years ago, the nation was embarking in a world war in which an old order would die and America would become the preeminent power in the world. Today America is challenged by rising powers as well as the resurgence of old adversaries while a war against terrorist organizations and non-state actors is waged across multiple domains. Strength, fortitude, courage, and ingenuity overcame a host of problems and challenges to the nation in the first 75 years of the existence of the Pentagon. Let us hope they continue to do so through the 21st century and beyond.