Analysis

Victory on Guadalcanal brought important strategic gains to the Americans and their Pacific allies but at high cost. Combined with the American-Australian victory at Buna on New Guinea, success in the Solomons turned back the Japanese drive toward Australia and staked out a strong base from which to continue attacks against Japanese forces, especially those at Rabaul, the enemy's main base in the South Pacific. Most important for future operations in the Pacific, the Americans had stopped reacting to Japanese thrusts and taken the initiative themselves. These gains cost the Americans 1,592 killed in action and 4,183 wounded, with thousands more disabled for varying periods by disease. Entering the campaign after the amphibious phase, the two Army divisions lost 550 killed and 1,289 wounded. For the Japanese, losses were even more traumatic: 14,800 killed in battle, another 9,000 dead from disease, and about 1,000 taken prisoner. On Guadalcanal General Hyakutake's troops gave American fighting men a chilling introduction to the character of the Japanese soldier: willing to fight to the death rather than surrender. Both navies lost twenty-four ships during the campaign but with a smaller industrial base to replace them, Japanese losses were more significant. Even more costly to Japan was the loss of over six hundred aircraft and pilots. U.S. Army-Navy coordination began poorly due in part to different views of the campaign's purpose. Ground commanders saw the campaign as an amphibious operation with the normal division of joint responsibilities. That is, naval forces would secure the seas around the objective for as long as it took ground forces to clear Guadalcanal of enemy. But higher Navy commanders viewed the operation as more of a raid than a formal amphibious campaign. They reserved the right to react to enemy naval operations as they saw fit without offering uninterrupted fire support to forces ashore, and they acted on that view by leaving Guadalcanal waters twice, in August and October. Later, Army and Navy commanders in the theater arrived at methods of operation generally satisfactory for the initial effort in a major war. For Army tactical leaders, Navy support proved most valuable when ground units operated close enough to the coast that destroyers' guns could reach into the jungled ravines so well fortified by the Japanese. Navy and Marine air support was always welcome but not always well aimed. On one occasion a dive bomber dropped ordnance on an infantry unit advancing toward Galloping Horse. Fortunately, such incidents proved the rare exception in close air support missions.

Intelligence about the island of Guadalcanal and Japanese forces on the island proved inadequate throughout the campaign. Before the effort began, the best information on terrain and soil conditions came from missionaries and planters expelled by the Japanese. But the recollections of these sincere but untrained observers were often of dubious quality, most of them more impressionistic than factual. As a result, ground commanders had to fight on Guadalcanal without accurate maps.

Once the fighting began, information continued to come from a jerrybuilt system of the most and least sophisticated methods available. At one end of the spectrum was the highly developed effort to intercept and to decipher enemy naval radio traffic. At the other was a network of 'coastwatchers,' native and Western informers in the jungle notifying the Americans by radio of Japanese ship and troop movements. In between, Generals Harmon, Vandegrift, and Patch could apply a number of military methods, including aerial photographic reconnaissance. On Guadalcanal the coastwatchers performed valuable service, but they could not be permanently integrated into military and naval intelligence systems. While no one doubted the courage of the coastwatchers, their communications with the ground commanders were indirect and intermittent, and they often had little more than an extremely localized view of the situation.

Even in their estimates of the situation on the ground, the four American division commanders in the campaign frequently underestimated the forces they faced, either in size or strength of fortification. The most grievous example occurred at the Gifu, where an enemy pocket originally estimated at 100 men with 10 crew-served weapons turned out to contain over 500 with 52 large weapons. The defenders ultimately held off five American battalions for a month, delaying the advance west long enough for the Japanese to evacuate 13,000 men from the island.

In their first combat experience, XIV Corps infantrymen carried out their missions with the mix of enthusiasm, hesitation, and incompetence characteristic of inexperienced troops. In the early stages of the campaign the troops allowed the Japanese to pin them down too often with light weapons. Compounding the error, commanders on the scene showed reluctance to resume the attack without a heavy artillery barrage. While this pattern of behavior may have faithfully conformed to contemporary doctrine, it played to a particular strength of the enemy. Artillery delays used up daylight hours, and the Japanese soon learned that American commanders did not like to initiate assaults in the last two or three hours before sunset. In contrast, the Japanese seemed to relish the onset of darkness and relied extensively on night movement to mount counterattacks and to position assault units and supporting arms for the next day. Until American soldiers stopped viewing sunset as the end of the tactical day and gained more expertise in night operations, they would continue to take unnecessary losses at the hands of their more experienced enemy.

Sloppy execution of routine infantry techniques cost some units unnecessary casualties. While approaching the Sea Horse on 10 January, Company K of the 35th Infantry began crossing a stream before properly checking the site or placing covering weapons on the flanks. With half the company on one bank and half on the other, the Japanese fired on the disorganized and vulnerable unit. Careful application of the basic principles of tactical movement, a responsibility of company grade officers and NCOs, would have prevented this disaster. Instead, it took two posthumous Medal of Honor performances to save the day for this company.

On another occasion a badly handled communication cost the 25th Division valuable time. During attacks on the Gifu strongpoint on 15 January, the executive officer of the 2d Battalion, 35th Infantry, ordered one platoon of Company G to withdraw. The order rapidly spread by word of mouth, and soon the entire battalion withdrew, costing the unit a full day's advance.