United States

Digital relief map of western United

Originally a federation of former British colonies that broke away from the Empire towards the end of the 18th century, the United States of America retained many of the best British legal traditions, including the British common law and the concept of parliamentary democracy, transformed into a republican form of government with a written Constitution as the supreme law of the land. Traditionally an agrarian and trading nation, with a strong commitment to freedom of the seas, the United States became an industrial powerhouse after the Civil War of 1861-1865. The U.S. Navy, which was previously limited to coastal protection and commerce raiding, began designing its first battleships in 1886 and was rapidly overtaking Britain as the supreme naval power by the end of the First World War. The Washington Naval Treaty successfully prevented an arms race between the two nations, and they grew increasingly aligned in their foreign policies between the wars in spite of the traditional American distaste for imperialism.

Though one of the victors of the First World War, the United States became strongly isolationist afterwards. Its Navy remained strong, but not nearly as strong as its industrial base and the disarmament treaties permitted. Its Army languished, becoming smaller than that of Romania by 1939. The German invasion of Poland found the United States almost completely unprepared for war, both materially and psychologically. However, Roosevelt and the liberal press gradually persuaded a skeptical nation that the Axis posed a deadly threat to liberal democracy, and that the United States should provide the Allies with all assistance short of war. The latter qualification was seriously stretched in the Atlantic, where German U-boats and U.S. destroyers were already shooting at each other by the time the attack on Pearl Harbor abruptly ended the great debate over the extent of American involvement in the war.

The United States had already begun military preparations before 7 December 1941, but there was not yet an American Expeditionary Force to send abroad, and the massive Navy buildup was still sitting on the ways of the nation's shipyards. However, the strong U.S. industrial base made it possible to equip, train, and supply a large Army, Air Force, and Navy, as well as equip and supply the Allies, and within three and a half years the Axis would be crushed.


In 1941, the United States extended across the North American continent from the Atlantic to the Pacific and controlled the Pacific territories of Alaska and Hawaii. There were additional small island outposts at Samoa, Wake, and Guam. The Panama Canal provided the means to shift forces quickly from the Atlantic to the Pacific. The Philippine Islands had the unusual status of a U.S. commonwealth on the road to full independence, which was promised in 1948. However, the United States had almost no bases along the crucial sea lanes to Australia, in part because the Neutrality Act prohibited the President from negotiating for bases with the (by then belligerent) powers with island possessions in the area until the  partial repeal of the Act in October 1941.

Geographically isolated from Europe and Asia by two wide oceans, the United States had become a naval power following the Civil War and continued to regard the Navy as the first line of defense following the First World War. With U-boats operating just offshore in the Atlantic, with landings by German saboteurs, and with sporadic Japanese I-boat raids on the Pacific coast, the American public's sense of security was badly shaken; but the Axis were never able to project meaningful power onto the American mainland, and the civilian population was spared many of the horrors of the Second World War.

The United States was rich in natural resources, including vast arable farmland in the Midwest; extensive forests in the Pacific Northwest; large oil fields in California, Texas, and elsewhere; vast coal fields in the Appalachians; and rich iron ore deposits in Minnesota. Of the major powers, only Russia came closer to self-sufficiency in raw materials. Of the materials that needed to be imported, nickel was readily available from Canada; manganese and chromium were available from Africa and Cuba, though the ore ships had to run the Atlantic U-boat gauntlet; tungsten and bauxite were available from South America; and sugar was available from the Caribbean. Tin and rubber would be in short supply following the Japanese conquest of Southeast Asia, but the United States would compensate by purchasing the entire South American tin production and by developing processes for manufacturing synthetic rubber from petrochemicals.

Some measure of the vast resources and productivity available to the United States is provided by the strength of the U.S. Navy in the Pacific in August 1945. By the end of the Pacific War, the United States Navy had 1137 warships, 14,847 combat aircraft, 2783 large landing craft and thousands of smaller landing craft, 400 advance bases, and 152 floating dry docks deployed in the Pacific.


The United States had the world's leading industrial economy, in spite of the lingering effects of the Great Depression. During the period 1939-1946, the U.S. produced almost half the world's steel; almost 60% of the world's aluminum; and about 70% of the world's merchant shipping tonnage. U.S. arms factories produced nearly twice as many tanks as Germany's, along with 65% of the world's trucks and 45% of the world's military aircraft. In fact, the United States outproduced the combined Axis powers in every important category.

Such production was possible for several reasons. Raw materials were abundant. American factories were all but immune to air attack. With a population of 132 million persons, American manpower was plentiful, and it was supplemented by large numbers of women and older men who were encouraged to join the work force to aid the war effort. American industrial management was the best in the world, making use of assembly lines and other methods of mass production that allowed the factories to employ semiskilled and unskilled labor. It did not hurt that the American population had a very high literacy rate and most Americans had a basic familiarity with mechanical systems.

Armed Forces

The vast majority of the soldiers, airmen, and sailors who fought under U.S. colors were civilian volunteers or draftees who lacked the professionalism of their counterparts in other nations. In spite of the heroic performance of U.S. forces at Midway, Guadalcanal, and other hard-fought Pacific battles, as well as Omaha Beach, the Bulge, and other European battles, careful statistical analysis demonstrates that, after material, position, and numbers are taken into account, the American soldier had only 70-80% of the fighting power of his German opponents. No comparable statistical comparison has been made with the Japanese, which would be difficult in any case because of the disparity in firepower.

Van Creveld (1982) has argued that the fighting power of the American soldier was reduced by flawed policies adopted during the rush to expand the armed forces rather than by any defect in national character. The decentralization of authority, careful selection and training of officers and men, and emphasis on the well-being of the soldiers that characterized the German army were absent in the American army, which chose a "scientific management" approach that paid almost no attention to the psychological needs of the soldier. The most glaring example of this was the atrocious replacement system, which all but guaranteed that the American soldier arriving in Europe would go into battle alongside strangers and remain there until he was killed or wounded or broke down mentally. Army planners appear to have believed that soldiers drawn from the free citizens of a democracy were certain to have better morale than the slave-soldiers of a dictatorship, until painful experience shattered such idealistic illusions.

These flaws were less evident in the Pacific, where the enormous lines of communication and the episodic nature of the battles allowed replacements to be absorbed into line units more effectively. In addition, the Marines had their own, more humane, replacement policy, and poor morale and lack of training seem to have been unheard of until the Okinawa campaign, where draftee Marines first saw combat and replacements came directly into the line. The resulting degradation of fighting strength is described by E.B. Sledge (1981) in his autobiographical account of the battle.

In the end, the Allied recipe for victory rested on the massive firepower and mobility available to American forces. American troops were normally lavishly equipped and supplied and were free in the use of firepower. No army of the Second World War was as thoroughly motorized as the American Army; only the British came close. Finally, Larrabee (1987) has argued that the "voluntary combination" characteristic of American culture worked in favor of combined arms operations, allowing infantry, armor, artillery (at which the Americans particularly excelled), and ground air support to work together effectively: "American combination is for certain purposes, while maintaining perfect freedom in all others, the individual in suspension within the group: the husking bee, the ridgepole raising, the wagon train westward, the jazz band, the street gang, the naval task force, the Army of the the Potomac. From the many, one."

U.S. Order of Battle


Ellis (1995)

Larrabee (1987)

Perret (1991, 1993)

Roberts (2011)

Sledge (1981)

Spector (1985)

Van Creveld (1982)

Willmott (1983)

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