At the end of World War I, there was no longer a balance of power in Europe. Great Britain and France had been physically devastated and were close to financial bankruptcy; Germany had been defeated and disarmed; Russia, by then the Soviet Union, had been excluded as a result of the Russian Revolution (1918–1921) and the spread of communism. The United States had withdrawn from European affairs, devoting its attention to the Western Hemisphere and the Pacific and leaving Britain and France as the only real powers in an unstable political and military system. France decided to strengthen its border defenses, known as the Maginot line, using the Treaty of Versailles (1919) to prevent the rearmament of Germany and entering into a series of security alliances. Great Britain, perceiving no serious threat, returned to the advancement of its imperial interests, relying upon its navy for defense. Although both Britain and France belonged to the League of Nations created at the end of World War I, neither saw this organization as a credible deterrent to war.
While World War I was the first global war to employ the advanced destructive capabilities of modern weapons systems and armaments, it was World War II that brought modern tactical and strategic thinking to their application. The result was destruction of human life and property on a scale unprecedented in history.
At the end of World War I, there was no longer a balance of power in Europe. Great Britain and France had been physically devastated and were close to financial bankruptcy; Germany had been defeated and disarmed; Russia, by then the Soviet Union, had been excluded as a result of the Russian Revolution (1918–1921) and the spread of communism. The United States had withdrawn from European affairs, devoting its attention to the Western Hemisphere and the Pacific and leaving Britain and France as the only real powers in an unstable political and military system. France decided to strengthen its border defenses, known as the Maginot line, using the Treaty of Versailles (1919) to prevent the rearmament of Germany and entering into a series of security alliances. Great Britain, perceiving no serious threat, returned to the advancement of its imperial interests, relying upon its navy for defense. Although both Britain and France belonged to the League of Nations created at the end of World War I, neither saw this organization as a credible deterrent to war.
With the exception of the persistent threat of communism, the 1920’s witnessed a lessening of international tensions, with the drafting of the Locarno Pact (1925), establishing Germany’s western borders; the Kellogg-Briand Pact (1928), renouncing the use of war in settling international disputes; and the entrance of Germany into the League of Nations (1926).
Everything changed, however, after the U.S. stock market collapsed in 1929. Financial and economic crisis brought political instability and a renewal of international tensions. On January 30, 1933, Adolf Hitler came to power in Germany. Italy began to assert its authority under fascist dictator Benito Mussolini, and Fascism spread into Romania and Hungary, as the rest of Eastern Europe began to disintegrate. At the same time, communist activities directed by Communist International (Comintern), the communist organization founded by Vladimir Ilich Lenin, under the control of the Soviet Union increased. Governments were forced to direct all available resources to provide social services for the large numbers of unemployed and destitute.
International tensions escalated after Hitler began to rebuild German military power. In 1933, after the League of Nations refused to weaken the restrictions on German rearmament, Hitler’s Germany left the organization. In 1935 the Saar was returned to Germany in response to a wave of Nationalist propaganda, and Hitler then attempted to take over Austria. Britain and France were able to thwart Hitler but only with the support of Mussolini, who allied with Hitler two years later when Britain and France refused to support his conquest of Ethiopia.
In 1936 Hitler and Mussolini also sent aid to Nationalist general Francisco Franco in Spain at the beginning of the Spanish Civil War, whereas the West relied on sanctions and weak protests. By 1936 Germany under Hitler and his National Socialist Party (Nazis) had begun to rearm at a frantic pace, whereas Britain, France, and the United States used almost all of their resources to bolster their economies. However, it should be noted that a considerable amount of the Works Progress Administration (WPA) spending in the United States was devoted to military purposes, including the building of two aircraft carriers and several military posts. Britain, in the meantime, had devoted a large portion of its 1936, 1937, and 1938 defense budgets to the building of radar stations and the infrastructure of an early warning system.
In 1936 military-age Germans outnumbered their French counterparts two to one. France, the key to Allied defense against Nazi aggression, realized that it would be unable to match either German manpower or German industrial production. For a short time, the French government actively sought an alliance with the Soviet Union, but this alliance never materialized, due to the purges of Joseph Stalin in the late 1930’s. Increasingly forced to rely on a defensive strategy, France became more obvious in its weaknesses, taking no action when Hitler remilitarized the Rhineland in 1937.
Meanwhile, Britain had decided that some kind of accommodation or appeasement could be reached with Hitler, offering only perfunctory protests when Hitler remilitarized the Rhineland and carried out his Anschluss, or annexation, of Austria in early 1938. When Hitler demanded that something be done about Czechoslovakia, the British, with French acquiescence, decided to appease Nazi Germany rather than risk a war they were not prepared to fight. In September, 1938, the British and French leaders, Neville Chamberlain and Édouard Daladier, allowed Hitler to seize the Sudetenland, which included most of Czechoslovakia’s defenses and armament industries, in return for Hitler’s promise that he would meet with them to negotiate future problems. In March, 1939, Hitler violated the agreement and seized the rest of Czechoslovakia.
Neither France nor Britain had begun to rearm seriously until the crisis over the Sudetenland, and they thus negotiated from a position of weakness. For example, all the aircraft used by Britain to fight the Battle of Britain (1940) were manufactured after the Czech crisis. Although both France and Britain had begun to rebuild their military forces in early 1939, their action was too little, too late. When the Polish crisis escalated into war with the German invasion of Poland on September 1, 1939, neither France nor Britain was prepared to fight. In actuality, the military weakness of Britain and France encouraged German aggression and added to the crises that led to World War II.
The United States was even further behind its European allies in military development. Preoccupied with the efforts to deal with the Great Depression and perceiving no immediate external threat to national security, the U.S. Army was less prepared to wage war than it had been at any time since the Civil War. Ranked equally with Britain and Japan in naval power, in 1939 the United States was ranked seventeenth in overall military strength, behind both Spain and Romania. The U.S. armed forces had no tanks, few first-line fighter aircraft, and barely enough rifles for its army.
It should be remembered that the United States, disillusioned by the outcome of World War I, was determined to stay out of World War II. However, as British and French power in the Pacific diminished as a result of the fighting in Europe, the Japanese seized the opportunity to expand their influence in the region. Although the U.S. armed forces were in a weakened state, U.S. interests in the Pacific, mainly China and the Philippines, had to be protected. A series of crises, misunderstandings, and miscalculations on both sides resulted in the Japanese decision to attack the United States Pacific Fleet at Pearl Harbor, Hawaii, on December 7, 1941. Unprepared, the United States suddenly found itself involved in World War II.
The military role of France during World War II was limited by its early defeat and surrender in 1940. Hampered both by its reliance on the fixed fortifications of the Maginot line and by its refusal to create a modern armored force, the French army was neither doctrinally nor technically capable of defeating the Germans. Later in the war, however, the First French Army, equipped and supplied by the United States and commanded by General Jean-Marie-Gabriel de Lattre de Tassigny, performed well and helped to liberate France.
One key to Allied success in the war was American industrial might. Here women at Douglas Aircraft’s Long Beach, California, plant assemble nose cones for A-20 attack bombers. (National Archives)
The British army did no better than the French. Defeated on the frontier of France in 1940, it was forced to retreat to Dunkirk and had to be evacuated, leaving behind all of its heavy equipment. Only in the initial battles against the Italians in North Africa did the British army emerge victorious. The Royal Air Force did perform better: With their Spitfire and Hurricane fighters, both guided by sophisticated early-warning radar systems, they were able to defeat the German air force, or Luftwaffe, and prevent the invasion of Britain. At the same time the heavy bomber force under British air marshal Arthur T. Harris, after concluding that daylight bombing would be too costly, began the successful development of night bombing operations. Harris developed the concept of “saturation bombing”; in May, 1942, he attacked Cologne with 1,000 planes and destroyed 600 acres of the city. However, high losses of 970 bombers between May and November, 1942, hampered his efforts.
British military performance, even when supported by a large infusion of U.S. aid, improved little in the desert battles against German commander Erwin Rommel’s Afrika Korps. Problems with command and control, armor, and leadership led to numerous British defeats. At the same time, the British army in the Far East was outfought and outmaneuvered by the Japanese, resulting in one of the worst defeats in British history, at Singapore (1941–1942). The situation did begin to improve when British generals Harold Alexander and Bernard Law Montgomery reorganized the British Eighth Army and won the Battle of El Alamein (1942). At the same time the British army came increasingly under U.S. control, both logistically and tactically.
Although the United States had not been prepared to fight a war when the Japanese attacked Pearl Harbor, the nation quickly mobilized its vast resources and was able to launch offenses in both North Africa and the South Pacific within less than a year. Although its initial performance was unimpressive, the U.S. Army was victorious at the Battles of the Kasserine Pass (1943) and New Guinea (1943). Three factors played a major role in early U.S. victories: material superiority, command of the air, and adaptability to changing circumstances.
Due in large measure to the training provided by the government and armed forces service schools, senior officers were intellectually prepared for a global war. The logistical accomplishments of the Army and Navy were formidable. Despite initial problems and some brief shortages of critical supplies, the U.S. servicemen and their allies were amply supplied with everything they needed to fight the war. Another area of exceptional performance was the U.S. artillery, which used forward observers and new operational techniques. The U.S. artillery proved to be the most successful arm of the service, a fact repeatedly remarked upon by captured German soldiers.
The U.S. Army excelled in two other aspects of warfare: air and amphibious operations. In the air, using heavy bombers such as B-17’s and B-24’s, the U.S. Army Air Corps was able to destroy much of Nazi Germany’s infrastructure, making it very difficult to maintain production. In the Pacific the B-29’s were even more successful in destroying Japanese industrial production. Although strategic bombing did not win the war, as some prewar theorists had predicted, it did play a significant role in the defeat of the Axis Powers. Amphibious operations were very difficult, and much of the necessary equipment had to be developed during the war. Thanks to U.S. engineering and production genius, the United States was able to carry out successful landings on hostile beaches in both the European and Pacific theaters of operation. The most important amphibious operations were the landings during Operation Overlord on Normandy beaches launched on June 6, 1944 (D day), which marked the start of the final campaign of World War II.
British and American intelligence was able to break the German and Japanese codes during the war, thereby gaining advanced warning of enemy intentions. At Bletchley Park, 50 miles north of London, Britain assembled a large group of cryptologists, who successfully decrypted the German codes throughout the war, providing real-time intelligence to the commanders in the field. The Allied intelligence system was code-named Ultra, and its existence was not revealed until almost twenty years after the war ended. At the same time, U.S. cryptologists broke the Japanese codes. Despite this success, however, the United States was surprised by the Japanese attack on Pearl Harbor, and reliance upon the Ultra codes contributed to the failure of U.S. intelligence to realize the seriousness of the German attack in December, 1944, that resulted in the Battle of the Bulge (1944–1945).
Perhaps the greatest military achievement during World War II was the development and use of the atomic bomb by the United States. Rarely has a single weapon so changed the nature of warfare and the global balance of power. The decision to drop the atomic bomb, though controversial, hastened the end of the war.
World War II witnessed the development and deployment of a large number of weapons ranging from the M1 Garand rifle to the atomic bomb. Science and technology played a greater role in the operational aspects of World War II than in those of any other war in history. In fact, a whole new area of military operations, called operational analysis, developed from the application of science to military problems. Operational analysis dealt with everything from the best depth at which to set depth charges to the most efficient force structure for combat divisions.
During the 1920’s and 1930’s the British experimented with a wide variety of armored vehicles, as well as other weapons systems. However, due to a lack of funding and a perceived lack of a serious military threat, these experiments were carried no further. The British went to war in 1939 with an army that was essentially equipped with slightly upgraded World War I weapons, except for the Spitfire and Hurricane fighters and some heavy bombers, which were developed late in the war. This failure in military modernization resulted in an increasing reliance throughout the war upon U.S. weapons, especially tanks and armored vehicles. After its defeat in 1940, the reconstituted French army that fought alongside the Allies in 1944 and 1945 relied almost entirely upon American weapons.
Within a year after the U.S. entry into the war, it had become the “Arsenal of Democracy,” providing weaponry and supplies for all of the Allies, including the Soviet Union. At the same time, it equipped the ninety-division U.S. Army with excellent weapons. The standard infantry weapon was the M1 Garand, which was a gas-operated, clip-fed, semiautomatic rifle that fired eight shots and weighed 9.5 pounds. The artillery, especially the 105-millimeter howitzer and the 155-millimeter gun, used the fire-control system developed early in the war and proved to be the most effective arm of the army.
In the air, the U.S. heavy bombers (B-17’s, B-24’s, and B-29’s) and fighters (P-47’s and P-51’s) were dependable and proved capable of defeating their adversaries. One of the less well known technical triumphs of American ingenuity was the proximity (V.T.) fuse. Actually a small radar set built into an explosive shell, it was so effective that no one was allowed to fire it over land, for fear the enemy might get their hands on one that did not explode. The greatest success of American technology was the atomic bomb, which hastened the end of the war against Japan and revolutionized warfare.
The greatest failure of American weaponry was the M4 Sherman medium tank. Although the reliable Sherman tank was capable of performing most of the tasks assigned to it, it had not been designed to be an antitank weapon and failed when called upon to engage the German medium or heavy tanks known as Panthers and Tigers. Produced in large numbers, more than 40,000, it provided armor not only for the U.S. Army but also for the British, French, and Polish forces in Europe. The M26 Pershing, which was designed to fight other tanks, was introduced at the end of the war but arrived too late to have any real effect. Only 700 Pershings were shipped to Europe.
At the beginning of World War II, the British Expeditionary Force (BEF) was dispatched to France. While retaining its independence, it served under the French commander General Maurice-Gustave Gamelin and later General Maxime Weygand. Organized into two army groups, the French concentrated the bulk of their mobile forces in the north with the BEF. After the defeat of France and the evacuation of the BEF to Dunkirk, most of the French army became a home-defense force. The remainder, along with Commonwealth forces, were sent to North Africa, whereas the British army stationed in India under separate command was used to reinforce the defenses in the Near East and Asia.
After the United States entered the war, the British army, although more experienced, came under U.S. field command. At the highest levels, the military command structure was the Combined Chiefs of Staff, consisting of the U.S. Joint Chiefs of Staff and the British Imperial General Staff. Although the Combined Chiefs of Staff operated on the principle of unanimity, the United States was decidedly the dominant partner. The staffs of both countries became more elaborate as the war progressed. The U.S. Joint Chiefs of Staff became increasingly involved in the formulation of U.S. foreign policy during the war. When the North African campaign began, the Free French were brought in as a junior partner. However, this relationship remained tenuous throughout the war because of President Franklin D. Roosevelt’s personal distrust of the French leader, General Charles de Gaulle. Although the Soviet Union was an ally, it was seldom involved in military decisions at the strategic or tactical level.
The war was fought by the Allies–mainly the United States, Britain, and France–in four theaters of operation. The European theater was commanded by U.S. general Dwight D. Eisenhower, who had taken direct control over the cross-Channel invasion, prompting Field Marshal Alexander to take control of the Italian campaign. In the Pacific theater, the Southeast Pacific was commanded by General Douglas MacArthur, the Central Pacific by Admiral Chester W. Nimitz, and the China-Burma-India theater by Admiral Louis Mountbatten.
For a brief period during the Guadalcanal campaign in the Solomon Islands, there was a further division called the South Pacific theater, commanded by Admiral William F. Halsey. In all of these commands there were joint staffs of U.S., British, and other Allied officers. The Americans were in command and provided most of the forces who fought in all theaters, except the China-Burma-India theater. One major difference in operations should be noted: in the European theater of operation, Commonwealth–mainly Canadian–troops remained as part of the British command, whereas in the Southwest theater of operations, the Australian army served directly under MacArthur.
The reconstituted French army served not as a separate force but rather as one of the armies under U.S. command. One of the primary reasons for this arrangement was U.S. responsibility for logistical support. At the end of the war, the First French Army was separated and given its own sector of Germany to occupy.
Cooperation between the Western Allies and the Soviet Union was difficult at best. At the beginning of the war, due to British resistance to an early cross-Channel invasion, U.S. staff officers had been more favorable to the Soviet Union. However, as the war progressed and Soviet intentions in Eastern Europe became apparent, the U.S. Joint Chiefs of Staff became increasingly hostile to the Soviets. The resulting mutual suspicion contributed to the beginning of the Cold War.
A nation’s military doctrine generally determines the nature of its weapons development, strategy, and tactics. During the years immediately following World War I, all the major powers reevaluated their military in the light of lessons learned in that war. The French came to the conclusion that defensive fortifications such as Verdun were their best option along with an infantry force supported by artillery and some armor. They believed that such a force would be able to take the offensive only in a limited way, using armor basically as mobile artillery to support the infantry rather than as an independent force capable of disrupting the enemy’s lines.
Britain experimented with a variety of armor operations during the interwar years. For example, General Sir Percy Hobart conducted deep penetration armor maneuvers in 1935. However, the lack of adequate funding and the absence of a clear threat limited any deployment to small units more suitable for use as an empire constabulary rather than a continental army.
Some American planners such as Colonel George Patton did conceive of the use of large armored formations but the absence of any real threat, the financial restraints created by the Great Depression, and the conviction that the United States would not be involved in a European war in the future resulted in inadequately trained and equipped forces. The U.S. Army and many planning staff did develop very extensive plans (the Rainbow Plans) and realized many of the possible difficulties that were found later in the war. For example, under the leadership of Marine major Earl H. Ellis, doctrine and planning for amphibious warfare was developed prior to the war.
By not entering the war until December of 1941, American planners were able to take advantage of the experiences of both the Allies and the Germans. The decision to create only a ninety-division army hampered some operations, especially the large-scale armor attacks favored by the Germans and the Soviets. Much of American doctrinal development during the war centered on the use of the vast material advantage that the United States possessed, especially in artillery and airpower.
In the area of airborne operations, the U.S. Army developed the doctrine, organization, equipment, and tactics during the early part of the war. After basing much of their development on reports of German successes in 1939 and 1940, the U.S. airborne units and their British counterparts proved to be some of the most effective fighting forces in the European theater of operations, despite their limited use. The 82nd and 101st Airborne Divisions were considered two of the best.
From the beginning of U.S. involvement in the war, the Allied strategy was “Europe first.” Although unable to launch a cross-Channel invasion in 1942, the Allies attacked Germany first in North Africa (Operation Torch) and then in Sicily (Operation Huskey). At the same time priority was given to the heavy bomber offensive against Germany.
After the successful landings at Normandy, Allied strategy in Europe was a broad-front strategy. Rather than concentrate on one or two major thrusts, as the British commander Field Marshal Montgomery advocated, Eisenhower opted to attack along the entire front, forcing the German army to retreat back into Germany and ultimately destroying its ability to fight. Probably the greatest failure of American strategy was Eisenhower’s decision to stop his advance at the Elbe River, allowing the Soviets to take Berlin and consequently to occupy all of Eastern Europe.
In the Pacific, General MacArthur directed an island-hopping strategy that avoided Japanese strong points. At the same time, the Japanese were further stretched by the U.S. decision to shift the axis of their attacks along two fronts: the Southwest Pacific from New Guinea through the Philippines and the Central Pacific. The Japanese surrendered before they were actually invaded.