The U.S. Army's extensive amphibious campaigns in the Southwest Pacific Theater during World War II have been all but forgotten today. The conduct of those far-flung operations, the sustenance of more than twenty-seven U.S. Army infantry divisions, and the imaginative planning required for bold thrusts deep into the enemy's rear areas offer timeless lessons for commanders. Moreover, a new aspect of the Pacific War has recently surfaced: the ability of the U.S. Army to read the most secret Imperial Japanese Army (IJA) codes--in short, to "see deep" for the purposes of operational planning. This Leavenworth Paper correlates, insofar as possible, the influence of Ultra intelligence on the conduct of General Douglas MacArthur's Aitape, New Guinea, campaign. The signals intelligence community regarded the U.S. XI Corps's destruction of the Imperial Japanese 18th Army as one of the singular achievements of the intelligence craft during World War II.

Nevertheless, no matter how accurate one's intelligence information or how superior one's forces, in the final analysis it still falls to the infantryman to destroy the enemy. It is true that MacArthur's Aitape invasion in April 1944 caught the Japanese totally unprepared, and it is also true that Ultra-derived intelligence revealed to the Allies the Japanese plan of attack against the U.S. covering force along the Driniumor River, about twenty miles cast of Aitape. Despite the abundance of available intelligence, the Japanese achieved tactical surprise, broke through the U.S. defenders, and precipitated a month-long struggle in the primeval New Guinea jungle terrain.

Dr. Edward J. Drea's use of interviews he conducted with U.S. Army veterans of the fighting adds the personal dimension to the campaign. Former riflemen described their experiences during the bitter campaign of attrition. By combining these first-person accounts with published sources and official Japanese and American records of the battle, the nature of jungle fighting and the tactics of both sides come into focus. The apparent lack of solid doctrinal basis for jungle fighting in either army is significant. Commanders at the highest level applied conventional tactics, despite the nature of the terrain, and ignored General George S. Patton's dictum that "there is no approved solution to any tactical situation." By the very brilliance of his operational maneuver, however, General MacArthur was able to capitalize on such orthodox or "approved" tactics on the Driniumor.

Dr. Drea has adopted a twofold approach to the Aitape campaign. In the first part of his Leavenworth Paper, he examines the strategic and operational levels of the battle, particularly command decision making and its relationship to Ultra. The second part of the paper, however, shifts the center of attention to small unit tactics, usually at the company level and below, because the jungle terrain fragmented units operating within it. In this section, the author deals with such basic questions as combat motivation, effects of prolonged combat, and unit cohesion. The 112th Cavalry Regiment serves as the centerpiece of part two, and its fate becomes intertwined with that of the attacking Japanese units. While the focus is on the human dimension, Dr. Drea reminds the reader of the strategic and political context in which the battle was fought.

Weapons, tactics, mobility, and national strategy evolve over time. No one would suggest a one-for-one transposition of 1944 doctrine and its application to the 1980s. The human factor in wartime, however, does remain unchanged. The reasons that American and Japanese soldiers fought and died in the New Guinea rain forests ultimately return to leadership and unit cohesion-the intangibles of combat that are crucial to success on any battlefield.