As in most countries, in the United States "national defense" is usually officially construed as the pursuit of all national interests by military means. Because of its location between two oceans, the weakness of its immediate neighbors, and the fortuitous presence of the Royal Navy during the nineteenth century, the United States seldom had to "defend" itself in any literal sense. Not until the advent of long-range nuclear weapons in the mid-twentieth century did the United States face a serious threat to its survival. The terrorist attacks on New York and Washington, D.C., in September 2001 introduced a new challenge to American "national defense," one without precedent in the nation's history.
In 1789 the new U.S. Constitution gave the federal government powers to provide for the common defense, balanced by state control of the militia and the right of the citizenry to bear arms. The Congress was empowered to levy taxes, declare war, raise armies, and provide for a navy. The president was named commander in chief of the army and navy and in 1795 received authority to call out the militia to execute the laws, suppress insurrection, and repel invasion. The Militia Act of 1792 established the principle of universal obligation to military service for all free white male citizens between the ages of 18 and 45.
From a strength of 750 men at the time of George Washington's inauguration, the regular army (established in 1775) grew to about 9,000 on the eve of the War of 1812. The Marine Corps was also founded in 1775. The navy, reestablished formally in 1798, gained valuable experience in the undeclared Quasi-War with France (1798–1800) over neutral maritime rights and in later operations against Tripolitan corsairs. President Thomas Jefferson (1801–1808) cut back both the army and the navy, relying for defense mainly on the militia and harbor fortifications supplemented by gunboats. His administration did see the founding of the U.S. Military Academy at West Point (1802) and the acquisition of the vast Louisiana Territory (1803).
The War of 1812, fought with Great Britain over the issue of neutral maritime rights, demonstrated the inadequacy of a national defense based on militia and maritime commerce raiding. The British, although absorbed in the struggle with Napoleon until 1814, were able to defend Canada successfully, sweep the tiny American navy from the seas, and penetrate the Atlantic and Gulf coast defenses at several points.
During the century after 1815 the United States poured its energies into economic growth, territorial expansion, and domestic politics. Thanks mainly to British concurrence and sea power, the hemispheric hegemony rashly proclaimed by the Monroe Doctrine in 1823 met no serious challenge. Up to the Mexican-American War (1846–1848) the army's normal strength hovered around 6,000, mostly scattered along the advancing frontier and engaged in sporadic clashes with the Indians. The navy's few frigates and sloops watched for slave traders and showed the flag. Still committed to the militia tradition, Congress in 1821 rejected Secretary of War John C. Calhoun's plan for a professional peacetime army that could be expanded rapidly in an emergency.
In both regular services, meanwhile, a new professionalism was emerging, nurtured both at West Point and at the Naval Academy, established at Annapolis in 1845. The war with Mexico growing out of the annexation of Texas was fought largely with the regulars and volunteer forces raised by the states. Victory brought annexation of most of the remaining areas west of the Mississippi.
The Civil War (1861–1865) remains the costliest war, in relative human and material terms, in American history. Its demands far exceeded the meager capabilities of the existing military system. Only a handful of regular officers proved equal to the test of higher command, and the tiny regular army remained mostly on the western frontier. Both sides resorted to conscription, mainly as a spur to volunteering. Militia, as such, served only as state local defense forces. By the end of the war, the Confederate government was attempting to control or operate such essential activities as munitions production and blockade-running, anticipating the rigors of twentieth-century "total" war.
After 1865 the army went back to protecting the frontier against Indian raids, and the navy returned to patrolling distant stations. Until the 1890s the army's strength remained in the neighborhood of 25,000, with a strong cavalry component to combat the Plains Indians. In the 1880s the seacoast fortifications were modernized, and the navy began belatedly to replace its wooden sailing ships and smooth-bore guns with modern vessels and armament. By 1898 it had a powerful fleet built around five battleships.
The war with Spain (1898–1899) was a response to U.S. expansionist pressures. Victory, won with relative ease, gave the United States possessions in the Caribbean and the Pacific, including the Philippines, which reacted with an armed revolt against the United States that took several years to suppress.
To protect its new empire and play its new world-power role, the United States expanded and modernized its armed forces in the early twentieth century. The reforms of Elihu Root gave the army a modern general staff organization and a system of advanced professional education on the European model. Spurred by Alfred Thayer Mahan's doctrines of sea power and its new imperial responsibilities, the United States had become by 1914 the third strongest naval power.
The European war that erupted in 1914 impinged on American interests in many ways—through the strangling of trade with European neutrals and the Central Powers, through the growth of a munitions industry fattened by foreign arms contracts, and through loss of American lives and property on neutral merchantmen attacked by German submarines. Responding to a popular clamor for "preparedness," the Defense Act of 1916 expanded the regular army and the National Guard and removed restrictions on federalization and use of the guard in an emergency, although it rejected the army proposal for a big volunteer federal reserve. In August 1916 Congress also voted a huge naval building program.
Although both sides in World War I violated neutral maritime rights, the United States in April 1917 came in on the side of the Triple Entente. In the next nineteen months some 4 million men were mobilized, of whom about half were sent to France and played a part in the final battles of 1918. These forces were raised by a federally administered selective draft, which, as in the Civil War, served also to stimulate volunteering. Dependent on its allies for most of its armament, the United States supplied large quantities of small arms, ammunition, food, and raw materials to them and contributed substantially in warships and merchant shipping to the defeat of the German submarine.
In the succeeding two decades the development of the long-range bomber and naval aircraft carrier exposed the United States itself, for the first time since the disappearance of sailing navies, to the real possibility of attack from other continents. In the 1930s, moreover, the growth of Japanese power and ambitions threatened American interests in the Pacific and Far East, while the rise of Nazi Germany in alliance with Italy and Japan raised the specter of a hostile militarism wielding global power.
The navy was the nation's first line of defense during this period. But at the Washington Naval Conference of 1921–1922, the leading nations had agreed to limitations on naval strength and construction, which had the practical effect of giving Japan naval supremacy in the western Pacific. Meanwhile, in a climate of popular revulsion against war, meager appropriations and declining enlistments reduced the regular army, National Guard, and newly created Federal Organized Reserve far below authorized levels. The army's air forces embraced the new doctrine of strategic air power, and the ground forces and marines experimented with new techniques of mechanized and amphibious warfare. But on the eve of World War II, the army had only a handful of modern aircraft and tanks.
During the 1930s the administration of Franklin D. Roosevelt (1933–1945) tried to foster hemispheric solidarity against Axis propaganda and economic penetration, and in 1938 it broadened national defense commitments to embrace the hemisphere. But in 1940, with the German conquest of most of western Europe, the United States suddenly faced the threat of German-Italian naval supremacy in the Atlantic and air attacks on South America from West African bases, while its fleet was pinned down in the Pacific watching Japan. Reacting to this threat, the United States instituted selective service and launched a massive rearmament program that year while negotiating with other hemisphere nations and Great Britain for base rights and military collaboration.
Hemisphere defense was closely linked with material aid to Great Britain, the Soviet Union (after June 1941), and other nations opposing the Axis. Under the Lend-Lease Act of March 1941, the United States eventually transferred to anti-Axis nations $50.2 billion in war matériel and services. During 1941, in collaboration with Britain, the United States occupied Iceland and other Atlantic bases, convoyed Allied shipping, exchanged shots with German submarines, ferried Britishtroops, and helped plan the eventual defeat of Germany. In 1941, with German armies bogged down in the Soviet Union and with Great Britain apparently safe from invasion, the pace of American rearmament was slowing. At this juncture Japan, after fruitless negotiations for U.S. recognition of its regional hegemony, struck without warning on 7 December at U.S. bases at Pearl Harbor, Hawaii, and in the Philippines, and simultaneously moved against British, French, and Dutch possessions in Southeast Asia. Germany and Italy declared war on the United States a few days later.
In World War II the United States mobilized forces of 15 million men and women, about one-quarter of the total anti-Axis coalition; mounted large-scale campaigns in the Mediterranean, Europe, the Pacific, and Burma; and provided the backbone of a crushing material superiority over the Axis powers.
For a quarter-century after World War II the United States was the most powerful nation on earth. Yet its leaders perceived a threat to its very survival from a hostile and expansionist world communism. American fear of communism dated back to the 1920s, but its immediate source was the split with Moscow over the postwar settlement in Eastern Europe and Germany. Suspicious of its former allies and concerned for its future security, the Soviet Union after 1944 rapidly occupied and communized Eastern Europe, rejected an American proposal for international control of atomic energy, and in 1949 developed its own atomic bomb.
In 1947 Congress placed the armed services (including a separate air force) with the joint chiefs of staff under a single secretary and Department of Defense. In 1949 the United States joined with Canada and ten (eventually thirteen) European nations in a mutual defense pact, the North Atlantic Treaty Organization (NATO), bolstered by integrated forces organized under a single headquarters and an American supreme commander. NATO was the first in a global network of U.S.-sponsored regional mutual security pacts formed during the 1950s, embracing forty-two nations and supplemented by a vast system of military bases and communications and by permanent fleets in the Mediterranean and western Pacific.
In 1950 a Soviet-supported North Korean invasion of South Korea precipitated a major limited war (1950–1953) involving large-scale intervention by the Chinese Communists, who had been victorious in the Chinese civil war of 1947–1949, and deployment of U.S. forces to a peak strength of 350,000 in a combined UN force of 800,000.
During the administration of Dwight D. Eisenhower (1953–1960), Secretary of State John Foster Dulles proclaimed a strategy of "massive retaliation" to deter open or covert Communist aggression. The new strategy ostensibly relied primarily on strategic air power and nuclear weapons, elements favored in post-Korea military force structures. It also involved American aid to anticommunist governments in Taiwan, Thailand, South Vietnam, Iran, Israel, Turkey, Greece, and Pakistan.
In 1957 the Soviets developed their first intercontinental ballistic missile, ending the virtual immunity of the U.S. homeland to nuclear attack and creating a "balance of terror" between the two superpowers. With the advent of nuclear-powered missile-launching submarines and "hardened" missile sites in the 1960s, each side gained an "assured destruction capability" against the other's cities. The fragility of this deterrent standoff was demonstrated to a frightened world in October 1962 when U.S. intelligence discovered that the Soviets were attempting to offset American superiority in long-range missiles by secretly shipping shorter-range missiles to Communistruled Cuba. After a short, but tense confrontation, Moscow backed down and withdrew the missiles.
By the end of the 1960s the Soviet Union had achieved virtual parity with the United States in strategic nuclear weapons and was expanding its naval power. To avert an apparently imminent Communist takeover in South Vietnam in 1965, the Johnson Administration initiated heavy bombing of North Vietnam and large-scale deployment of combat forces in the south. North Vietnamese forces, supplied by the Soviet Union and China, began to move into the south at about the same time. Four years later, the United States had more than 600,000 troops in Southeast Asia, most of them in South Vietnam.
The turning point came in 1968, when the Communist Tet offensive convinced U.S. leaders that the war could not be won at acceptable cost. President Johnson halted the bombing of North Vietnam, initiated peace negotiations, and withdrew from the presidential election. After Richard Nixon's election to the presidency in 1968, he continued negotiations and gradually withdrew American forces from South Vietnam, while the Vietnamese were being trained and equipped to carry on alone. In 1973 the United States ceased military operations in Vietnam, and in 1975 Saigon fell to the North Vietnamese army. The war, the most unpopular in American history, cost 58,000 American lives, with annual expenditures that soared to $28.8 billion in 1969. American bombers dropped three times as much tonnage as in all of World War II. Use of the draft as the primary source of military manpower, reversing the Korean War policy of reliance on reserves, intensified popular antiwar feeling. In 1973 selective service was terminated, and the armed forces reverted to their traditional reliance on voluntary enlistments.
During the 1980s the Reagan Administration implemented the largest peacetime military buildup in American history. The end of the Cold War led many to question the need for such a large military and substantial defense cutbacks began. In 1991, however, the United States went to war in the Persian Gulf, and throughout the decade the use of American military force abroad increased, particularly in Somalia in 1992–1993 and the former Yugoslavia in 1995 and 1999.
In the wake of the terrorist attacks of 11 September 2001, the United States faced the most immediate threat to its national security since Pearl Harbor. The Bush Administration responded by attacking terrorist base camps in Afghanistan and commencing a massive defense buildup on par with the Reagan defense program of the 1980s. Most national security experts have concluded that terrorism poses a major threat to American security in the twenty-first century, and the military will increasingly be molded to respond effectively to that challenge.
Bibliography
Millett, Alan Reed, and Peter Maslowski. For the Common Defense: A Military History Of the United States of America. New York: Free Press, 1994.
Millis, Walter. Arms and Men: A Study in American Military History. New York: Putnam, 1956.
Perret, Geoffrey. A Country Made By War: The Story of America's Rise to Power. New York: Random House, 1989.
Weigley, Russell F. The American Way of War: A History Of United States Military Strategy and Policy. Bloomington: Indiana University Press, 1977.
—Richard M. Leighton/A. G.
