American Military History, Volume 2 by Richard W. Stewart

After more than a year and a half of rearming, the United States in December 1941 was still in no position to carry the war to its enemies. On December 7 the Army numbered some 1,644,000 men (includ- ing about 120,000 officers), organized into 4 armies, 37 divisions (30 infantry, 5 armored, 2 cavalry), and over 40 combat air groups. Three of the divisions were overseas (2 in Hawaii, 1 in the Philippines), with other garrison forces totaling fewer than 200,000. By spreading equip- ment and ammunition thin, the War Department might have put a substantial force into the field to repel an attack on the continental United States. Seventeen of the divisions at home were rated as techni- cally ready for combat but lacked the supporting units and the train- ing necessary to weld them into corps and armies. More serious still, they were inadequately equipped with many weapons that recent op- erations in Europe had proven indispensable (e.g., tank and antitank guns, antiaircraft artillery, radios, and radar); and some of these short- ages were aggravated by lack of auxiliary equipment like fire-control mechanisms.

Above all, ammunition of all kinds was so scarce that the War De- partment was unwilling to commit more than one division and a single antiaircraft regiment for service in any theater where combat operations seemed imminent. In fact, only one division-size task force was sent to the far Pacific before April 1942. Against air attacks, too, the country's defenses were meager. Along the Pacific coast, the Army had only forty- five modern fighter planes ready to fly and only twelve 3-inch antiair- craft guns to defend the whole Los Angeles area. On the East Coast, there were only fifty-four Army fighter planes ready for action. While the coastal air forces, primarily training commands, could be reinforced by airlift, in the interior of the country, the total number of modern fighter aircraft available was less than 1,000. Fortunately, there was no real threat of an invasion in force, and the rapidly expanding output of munitions from American factories promised to remedy some of these weaknesses within a few months. Furthermore, temporary diversions of Lend-Lease equipment, especially aircraft, helped to holster the overall defense posture within the first few weeks after Pearl Harbor. The Army hoped by April to have as many as thirteen divisions equipped and sup- plied with ammunition for combat.