During the summer of 1944, as the battles raged along both lines of advance, the strategic debate over the choice of Luzon versus Formosa also waxed hot. General MacArthur argued fervently that the proper course was to move through the Philippines to Luzon, cutting the Japanese lines of communications southward, establishing a base for bombardment and invasion of Japan, and fulfilling a solemn national obligation to liberate the Philippine people. Admiral Ernest J. King, Chief of Naval Operations, just as adamantly insisted that the war could be shortened by directing the Pacific advance from the Marianas and Palaus toward Formosa, the China coast, and Japan proper, seizing only the essential positions in the southern and central Philippines necessary to render air support for these advances. The arguments for Formosa were cogent enough. Its strategic position made it a better island steppingstone to the China coast or the Japanese home islands, a position from which Japanese communications to the south could be cut more effectively than from Luzon, and a closer-in position from which to conduct strategic bombardment. But it also could prove to be a more difficult position to take, and Nimitz did not have in his theater sufficient Army supporting and service troops, without reinforcement, to sustain a land campaign on the island. It might be difficult, too, to mount an invasion of Formosa as long as the Japanese could, from strong positions on Luzon, interfere with the Allied line of communications. Another consideration involved the real value of a foothold on the China coast. By the early fall of 1944, air base sites in east China Prom which the Allies had hoped to support Pacific operations and bomb Japan appeared irretrievably lost, and the Marianas already provided bases for the B-29's almost as close to Tokyo as Formosa. The need to seize and develop a port on the China coast thus lost much of its urgency, and the argument that Formosa was the best steppingstone to China became less compelling. Then, too, a successful invasion of either Luzon or Formosa required some concentration of forces from the two theaters. It was far easier to shift highly mobile naval resources in Nimitz' theater to the Philippines than it was to redeploy Army troops from the Southwest Pacific to support Nimitz' invasion of Formosa and the jump to the China coast with which he hoped to follow it.
At the time of the Morotai and Palaus landings, MacArthur's plans for invasion of the Philippines called for a preliminary assault in southern Mindanao on November 15, 1944, to secure air bases for the support of a larger attack at Leyte, in the east-central Philippines, on December 20. He would follow this with a large-scale assault on Lingayen Gulf in February 1945. Nimitz meanwhile planned to mount an invasion of Yap in the Carolines in October 1944 and then would prepare to launch his attack on Formosa as soon afterward as the elements of the Pacific Fleet required for operations in the southern and central Philippines could be returned. Obviously, there had to be a choice between Luzon and Formosa, for the Pacific Fleet would be required to support either operation.
The course of events went far to dictate the final choice. In mid-September Admiral Halsey's carrier task forces providing strategic support for the Morotai and Palaus operations struck the central and southern Philippines. Halsey found Japanese air strength unexpectedly weak and uncovered few signs of significant ground or naval activity. On the basis of Halsey's reports, MacArthur and Nimitz proposed to the Joint Chiefs a move directly to Leyte in October, bypassing Mindanao. Nimitz agreed to divert to the Leyte invasion the 3-division corps then mounting out of Hawaii for the assault against Yap. The Joint Chiefs quickly approved the new plan, and the decision to invade Leyte two months ahead of schedule gave MacArthur's arguments to move onto Luzon almost irresistible force. MacArthur now reported that he could undertake the invasion of Luzon in December 1944, whereas all the planners' estimates indicated that resources for an invasion of Formosa particularly service troops and shipping could not be readied before February 1945 at the earliest. Nimitz proposed to shift the Central Pacific attack northward against Iwo Jima in the Bonins in January 1945 and then against Okinawa and other islands in the Ryukyus early in March. On October 3, Admiral King bowing to the inevitable, accepted the new plans and the Joint Chiefs issued directives to MacArthur for the invasion of Luzon on December 20 and to Nimitz for the invasion of Iwo Jima and Okinawa early in 1945.
Pacific strategy had been cast into almost its final mold. In the end, the China coast objective disappeared entirely from planning boards. Final plans for the defeat of Japan envisaged gradual tightening of the ring by blockade and bombardment from the Marianas, Philippines, and Ryukyus with an invasion of the home islands to be mounted from these bases.
The main assault at Leyte took place on October 20, 1944, as four Army divisions landed abreast in the largest amphibious operation yet conducted in the Pacific. Vice Adm. Thomas C. Kinkaid, MacArthur's naval commander, controlled the amphibious phases, including naval gunfire support and close air support by planes based on escort carriers. Ground forces were under Lt. Gen. Walter Krueger, commanding the U.S. Sixth Army; land-based air forces of the Southwest Pacific Area in general support were commanded by Lt. Gen. George C. Kenney. MacArthur himself exercised unified command over the air, ground, and naval commanders. The fast carrier task forces of the Pacific Fleet, providing strategic support, operated under the control of Admiral Halsey, who reported to Nimitz, not MacArthur. There was no provision for unified naval command, and Halsey's orders were such that he could make his principal mission the destruction of the Japanese Fleet rather than the support of MacArthur's entry into the Philippines.
The Japanese had originally planned to make their stand in the Philippines on Luzon, but the invasion of Leyte moved them to reconsider, since they now decided that the entire Philippine Archipelago would be strategically lost if the U.S. Army secured a foothold in the central islands. They therefore began sending ground reinforcements to Leyte; increased their land-based air strength in the Philippines in the hope of destroying Allied shipping in Leyte Gulf and maintaining local air superiority; and dispatched their remaining naval strength to Leyte Gulf to destroy Kinkaid's invasion fleet and to block Allied access to the Philippines. The ensuing air-naval Battle of Leyte Gulf was the most critical moment of the campaign, and proved one of the most decisive actions of the Pacific war.
Admiral Halsey, without consulting MacArthur or Kinkaid, pulled the bulk of his carrier forces northward to intercept part of the Japanese Fleet, leaving Leyte Gulf open to other Japanese Fleet units. Gallant, desperate action by Kinkaid's old battleships and escort carrier planes turned back the Japanese in the gulf, assuring the safety of the landing forces. It had been a close thing, clearly demonstrating the dangers of divided command. In the end, however, the combined operations of Kinkaid's and Halsey's forces virtually eliminated the Japanese Navy as a factor in the Pacific war.
With the Leyte beaches secure, U.S. Army units proceeded to destroy the Japanese ground forces. Miserable weather bogged down the pace of operations, made supply difficult, delayed airfield construction, curtailed air support, and permitted the Japanese to continue to ship reinforcements to the island. The reinforcement program came to a sudden halt early in December when the 77th Division executed an amphibious envelopment on Leyte's west coast, and by late December the Sixth Army had secured the most important sections of the island, those required for air and logistical bases. Japanese troops in the mountains of northwestern Leyte continued organized resistance well into the spring of 1945, occupying the energies of large portions of Lt. Gen. Robert L. Eichelberger's newly formed Eighth Army.
While the fight on Leyte continued, MacArthur's forces moved on to Luzon only slightly behind schedule. The first step of the Luzon Campaign was the seizure of an air base in southwestern Mindoro, 150 miles south of Manila, on December 15, 1944, two Army regiments accomplishing the task with ease. The invasion of Luzon itself started on January 9, 1945, when four Army divisions landed along the shores of Lingayen Gulf. Command arrangements were similar to those at Leyte, and again fast carrier task forces under Halsey operated in general support and not under MacArthur's control. Within three days five Army divisions, a separate regimental combat team, two artillery groups, an armored group, and supporting service units were ashore and had begun a drive down the Central Plains of Luzon toward Manila. The Japanese were incapable of naval intervention at Lingayen Gulf, and their most significant reaction was to throw a number of kamikaze (suicide plane) attacks against Kinkaid's naval forces for four days.
General Tomoyuki Yamashita, commanding Japanese forces in the Philippines, did not intend to defend the Central Plains Manila Bay region, the strategic prize of Luzon. Knowing he would receive no reinforcements and believing the issue in the Philippines had been decided at Leyte, he sought only to pin down major elements of MacArthur's forces in the hope of delaying Allied progress toward Japan. For this purpose he moved the bulk of his troops into mountain strongholds, where they could conduct a protracted, bloody defensive campaign. But Japanese naval forces on Luzon, only nominally under Yamashita, decided to ignore this concept in favor of defending Manila and Manila Bay. Thus, when U.S. Army units reached Manila on February 3, it took them a month of bitter building-to-building fighting to root out the Japanese. Meanwhile, operations to clear Manila Bay had begun with a minor amphibious landing at the southern tip of Bataan on February 15. The next day a combined parachute-amphibious assault, involving two Army regiments, initiated a battle to clear Corregidor Island. Other forces cleared additional islands in Manila Bay and secured the south shore. By mid-March the bay was open for Allied shipping, but an immense salvage and repair job was necessary before the Allies could fully exploit Manila's excellent port facilities.
The reinforced 38th Division had landed meanwhile near Subic Bay and had cut across the base of Bataan peninsula to prevent the Japanese from holing up on Bataan as had MacArthur's forces three years earlier. The 11th Airborne Division undertook both amphibious and parachute landings in southern Luzon to start clearing that region, and the 158th Regimental Combat Team made an amphibious assault in southeastern Luzon to secure the Bicol peninsula. Turning against the Japanese mountain strongholds, MacArthur continued to pour reinforcements onto Luzon, and the land campaign there ultimately evolved into the largest of the Pacific war. MacArthur committed to Luzon ten divisions, two regiments of another division, and three separate regimental combat teams. Guerrillas also played a large role. One guerrilla unit came to substitute for a regularly constituted division, and other guerrilla forces of battalion and regimental size supplemented the efforts of the Army units. Moreover, the loyal and willing Filipino population immeasurably eased the problems of supply, construction, and civil administration.
Except for a strong pocket in the mountains of north central Luzon, organized Japanese resistance ended by late June 1945. The rugged terrain in the north, along with rainy weather, prevented Krueger's Sixth Army from applying its full strength to the reduction of this pocket. Eichelberger's Eighth Army took over responsibility for operations on Luzon at the end of June and continued the pressure against Yamashita's force in the last-stand area, but they held out there until the end of the war.
While Sixth Army was destroying Japanese forces on Luzon, Eighth Army ultimately employed five divisions, portions of a sixth division, a separate regimental combat team, and strong guerrilla units in its campaign to reconquer the southern Philippines. This effort began when a regimental combat team of the 41st Division landed on Palawan Island on February 28, 1945. Here engineers built an air base from which to help cut Japan's line of communications to the south and to support later advances in the southern Philippines and the Indies. On March 10, another regimental combat team of the 41st, later reinforced, landed near Zamboanga in southwestern Mindanao, and soon thereafter Army units began moving southwest toward Borneo along the Sulu Archipelago. In rapid succession Eighth Army units then landed on Panay, Cebu, northwestern Negros, Bohol, central Mindanao, southeastern Negros, northern Mindanao, and finally at Sarangani Bay in southern Mindanao, once intended as the first point of re-entry into the Philippines. At some locales bitter fighting raged for a time, but the issue was never in doubt and organized Japanese resistance in the southern Philippines had largely collapsed by the end of May. Mopping up continued to the end of the war, with reorganized and re-equipped guerrilla forces bearing much of the burden.
The last offensives in the Southwest Pacific Area started on May 1 when an Australian brigade went ashore on Tarakan Island, Borneo. Carried to the beaches by landing craft manned by U.S. Army engineers, the Australians had air support from fields on Morotai and in the southern Philippines. On June 10 an Australian division landed at Brunei Bay, Borneo, and another Australian division went ashore at Balikpapan on July 1 in what proved to be the final amphibious assault of the war.
Since slow-base development at Leyte had forced MacArthur to delay the Luzon invasion from December to January, Nimitz in turn had to postpone his target dates for the Iwo Jima and Okinawa operations, primarily because the bulk of the naval resources in the Pacific fast carrier task forces, escort carrier groups, assault shipping, naval gunfire support vessels, and amphibious assault craft had to be shifted between the two theaters for major operations. The alteration of schedules again illustrated the interdependence of the Southwest and Central Pacific Areas.
The Iwo Jima assault finally took place on February 19, 1945, with the 4th and 5th Marine Divisions, supported by minor Army elements, making the landings. The 3d Marine Division reinforced the assault, and an Army regiment ultimately took over as island garrison. The marines had to overcome fanatic resistance from firmly entrenched Japanese, who held what was probably the strongest defensive system American forces encountered during the Pacific war, and it took a month of bloody fighting to secure the island. In early March a few crippled B-29's made emergency landings on Iwo; by the end of the month an airfield was fully operational for fighter planes. Later, engineers constructed a heavy bomber field and another fighter base on the island.
The invasion of the Ryukyus began on March 26 when the 77th Division landed on the Kerama Islands, fifteen miles west of Okinawa, to secure a forward naval base, a task traditionally assigned to marines. On April 1 the 7th and 96th Divisions and the 2d and 6th Marine Divisions executed the assault on the main objective, Okinawa. Two more Army divisions and a Marine infantry regiment later reinforced it. Another amphibious assault took place on April 16, when the 77th Division seized Ie Shima, four miles west of Okinawa, and the final landing in the Ryukyus came on June 26, when a small force of marines went ashore on Kume Island, fifty miles west of Okinawa. Ground forces at Okinawa were first under the U.S. Tenth Army, Lt. Gen. Simon B. Buckner commanding. When General Buckner was killed on June 18, Marine Lt. Gen. Roy S. Geiger took over until General Joseph W. Stilwell assumed command on the 23d.
The Japanese made no attempt to defend the Okinawa beaches, but instead fell back to prepared cave and tunnel defenses on inland hills. Bitterly defending every inch of ground, the Japanese continued organized resistance until late June. Meanwhile, Japanese suicide planes had inflicted extensive damage on Nimitz' naval forces, sinking about 25 ships and damaging nearly In more in an unsuccessful attempt to drive Allied naval power from the western Pacific. Skillful small unit tactics, combined with great concentrations of naval, air, and artillery bombardment, turned the tide of the ground battle on Okinawa itself. Especially noteworthy was the close support that naval gunfire vessels provided the ground forces and the close air support furnished by Army, Navy, and Marine aircraft.
Capture of Okinawa and other positions in the Ryukyus gave the Allies both air and naval bases within easy striking distance of Japan. By early May fighter planes from Okinawa had begun flights over Japan, and as rapidly as fields became available bombers, including units from the Southwest Pacific Area, came forward to mount attacks in preparation for the invasion of the home islands. The forward anchorages in the Ryukyus permitted the Pacific Fleet to keep in almost continuous action against Japanese targets. The Ryukyus campaign had brought Allied forces in the Pacific to Japan's doorstep.
While American forces in the Pacific, under the unified direction of the U.S. Joint Chiefs of Staff, made spectacular advances, the Allied effort in Southeast Asia bogged down in a mire of conflicting national purposes. The hopes Americans held, in the early stages of the war, that Chinese manpower and bases would play a vitally important role in the defeat of Japan were doomed to disappointment. Americans sought to achieve great aims on the Asiatic mainland at small cost, looking to the British in India and the Chinese, with their vast reservoirs of manpower, to carry the main burden of ground conflict. Neither proved capable of exerting the effort the Americans expected of them.
Early in 1942 the United States had sent General Stilwell to the Far East to command American forces in China, Burma, and India and to serve as Chief of Staff and principal adviser to Chiang Kai-shek, the leader of Nationalist China and Allied commander of the China theater. Stilwell's stated mission was "to assist in improving the efficiency of the Chinese Army." The Japanese conquest of Burma, cutting the last overland supply route to China, frustrated Stilwell's designs, for it left a long and difficult airlift from Assam to Kunming over the high peaks of the Himalayas as the only remaining avenue for the flow of supplies. The Americans assumed responsibility for the airlift, but its development was slow, hampered by a scarcity of transport planes, airfields, and trained pilots. Not until late in 1943 did it reach a monthly capacity of 10,000 tons, and in the intervening months few supplies flowed into China. The economy of the country continually tottered on the brink of collapse, and the Chinese Army, although it was a massive force on paper, remained ill organized, ill equipped, poorly led, and generally incapable of offensive action.
Stilwell thought that the only solution was to retake Burma and reopen the land supply line to China, and this became the position of the U.S. Joint Chiefs of Staff. To achieve the goal Stilwell undertook the training and equipping of a Chinese force in India that eventually consisted of three divisions, and sought to concentrate a much larger force in Yunnan Province in China and to give it offensive capability. With these two Chinese forces he hoped to form a junction in north Burma, thus re-establishing land communications between China and India. Stilwell's scheme became part of the larger plan, ANAKIM, that had been approved by the Combined Chiefs of Staff at the Casablanca Conference. Neither the British nor the Chinese, however, had any real enthusiasm for ANAKIM, and in retrospect it seems clear that its execution in 1943 was beyond the capabilities of forces in the theater. Moreover, Chiang was quite dilatory in concentrating a force in Yunnan; Maj. Gen. Claire L. Chennault, commanding the small American air force in China, urged that the Hump air line should be used to support an air effort in China, rather than to supply Chinese ground forces. Chennault promised amazing results at small cost, and his proposals attracted President Roosevelt as well as the British and the Chinese. As an upshot, at the TRIDENT Conference in May 1943, the amphibious operation against Rangoon was canceled and a new plan for operations emerged that stressed Chennault's air operations and provided for a lesser ground offensive in central and northern Burma. Under this concept a new road would be built from Ledo in Assam Province, India, to join with the trace of the old Burma Road inside China. The Americans assumed responsibility for building the Ledo Road in the rear of Chinese forces advancing from India into Burma.
Logistical difficulties in India, however, again delayed the opening of any land offensive and kept the airlift well below target figures. Until the supply line north from Calcutta to the British and Chinese fronts could be improved and this job took well over a year both air and ground operations against the Japanese in Burma were handicapped. In October 1943 Chinese troops under Stilwell did start to clear northern Burma, and in the spring of 1944 a U.S. Army unit of regimental size, Merrill's Marauders, spearheaded new offensives to secure the trace for the overland road. But Myitkyina, the key point in the Japanese defenses in north Burma, did not fall until August 2 and by that time the effort in Burma had been relegated to a subsidiary role.
After the SEXTANT Conference in late 1943, in fact, the American staff no longer regarded it as probable that the overland route to China could be opened in time to permit Chinese forces to drive to the coast by the time American forces advancing across the Pacific reached there. While the Americans insisted on continuing the effort to open the Ledo Road, they now gave first priority to an air effort in China in support of the Pacific campaigns. The Army Air Forces, in May 1944, started to deploy the first of its B-29 groups to airfields in East China to commence bombing of strategic targets in Korea, Manchuria, and Japan. At the same time, Chennault's Fourteenth Air Force was directed to stockpile supplies for missions in support of Pacific forces as they neared the China coast. Again these projects proved to be more than could be supported over the Hump air line, particularly since transports had also to be used to supply the ground effort of both British and Chinese forces. Then the Japanese reacted strongly to the increased air effort and launched a ground offensive that overran most of the existing fields and proposed air base sites in east China. Both air and ground resources inside China had to be diverted to oppose the Japanese advance. The B-29's were removed to India in January 1945, and two months later were sent to Saipan where the major strategic bombing offensive against Japan was by that time being mounted. In sum, the air effort in China without the protection of an efficient Chinese Army fulfilled few of the goals proclaimed for it.
To meet the crisis in east China, President Roosevelt urged Chiang to place his U.S. supported armies under the command of General Stilwell; Chiang eventually refused and asked for Stilwell's recall, a request the President honored. In September 1944, Maj. Gen. Albert C. Wedemeyer replaced Stilwell as Chief of Staff to Chiang and commander of American forces in the China Theater; a separate theater in India and Burma was created with Lt. Gen. Dan I. Sultan as its commanding general. The command issue was dropped and the American strategy in China became simply one of trying to realize at least something from previous investments without additional commitments.
Ironically enough, it was in this phase, after the Pacific advances had outrun those in Southeast Asia, that objects of the 1942 strategy were realized, in large part because the Japanese, hard-pressed everywhere, were no longer able to support their forces in Burma and China adequately. British and Chinese forces advanced rapidly into Burma in the fall of 1944, and, on January 27, 1945, the junction between Chinese forces advancing from India and Yunnan finally took place, securing the trace of the Ledo Road. To the south, the British completed the conquest of central Burma and entered Rangoon from the north early in May. The land route to China was thus finally secured on all sides, but the Americans had already decided that they would develop the Ledo Road only as a one-way highway, though they did expand the airlift to the point where, in July 1945, it carried 74,000 tons into China.
With increased American supply support, Wedemeyer was able to make more progress in equipping and training the Chinese Army. Under his tutelage the Chinese were able to halt the Japanese advance at Chihchiang in April 1945, and, as the Japanese began to withdraw in order to prepare a citadel defense of their home islands, Wedemeyer and the Chinese laid plans to seize a port on the Chinese coast. The war came to an end, however, before this operation even started and before the training and equipping of a Chinese Army was anywhere near completion. Chiang's forces commenced the reoccupation of their homeland still, for the most part, ill equipped, ill organized, and poorly led.
During the summer of 1945, Allied forces in the Pacific had stepped up the pace of their air and naval attacks against Japan. In June and July carrier-based planes of the U.S. Pacific Fleet and U.S. Army Air Forces planes from the Marianas, Iwo Jima, and Okinawa struck the Japanese home islands continuously. During July Pacific Fleet surface units bombarded Japan's east coast, and in the same month a British carrier task force joined in the attack. Planes from the Philippines hit Japanese shipping in the South China Sea and extended their strikes as far as Formosa and targets along the South China coast. American submarines redoubled their efforts to sweep Japanese shipping from the sea and sever the shipping lanes from Japan to the Indies and Southeast Asia. Throughout the war, in fact, submarines had preyed on Japanese merchant and combat vessels, playing a major role in isolating Japan from its conquests and thereby drastically reducing Japan's ability to wage war.
After Germany's surrender in May the United States embarked upon a huge logistical effort to redeploy more than a million troops from Europe, the United States, and other inactive theaters to the Pacific. The aim was to complete the redeployment in time to launch an invasion of Japan on November I, and the task had to be undertaken in the face of competing shipping demands for demobilization of long-service troops, British redeployment, and civil relief in Europe. By the time the war ended, some 150,000 men had moved directly from Europe to the Pacific, but a larger transfer from the United States across the Pacific had scarcely begun. In the Pacific, MacArthur and Nimitz had been sparing no effort to expand ports and ready bases to receive the expected influx and to mount invasion forces. The two commanders were also completing plans for the invasion of Japan. In the last stage of the war, as all forces converged on Japan, the area unified commands were replaced by an arrangement that made MacArthur commander of all Army forces in the Pacific and Nimitz commander of all Navy forces.
By midsummer of 1945 most responsible leaders in Japan realized that the end was near. In June, those favoring peace had come out in the open, and Japan had already dispatched peace feelers through the Soviet Union, a country it feared might also be about to enter the war despite the existence of a non-aggression treaty between the two nations. As early as the Tehran Conference in late 1943 Stalin had promised to enter the war against Japan, and it was agreed at Yalta in February 1945 that the USSR would do so three months after the defeat of Germany. At the Potsdam Conference in July 1945 the Soviet Union reaffirmed its agreement to declare war on Japan. At this conference the United States and Britain, with China joining in, issued the famed Potsdam Declaration calling upon Japan to surrender promptly, and about the same time President Truman decided to employ the newly tested atomic bomb against Japan in the event of continued Japanese resistance.
Despite the changing climate of opinion in Japan, the Japanese did not immediately accept the terms of the Potsdam Declaration. Accordingly, on August 6 a lone American B-29 from the Marianas dropped an atomic bomb on Hiroshima; on the 9th the Soviet Union came into the war and attacked Japanese forces in Manchuria; and on the same day another B-29 dropped a second atomic bomb on Nagasaki. The next day Japan sued for peace, and, with the signing of surrender terms aboard the USS Missouri in Tokyo Bay on September 2, the bitter global war came to an end.
In winning the Pacific war the Allies had found it unnecessary to press home their attacks and destroy the Japanese military forces except for the Japanese Fleet. By the end of the war Japan's Navy had virtually ceased to exist; Japanese industry had been so hammered by air bombardment that Japan's ability to wage war was seriously reduced; and U.S. submarine and air actions had cut off sources of raw material. At the time of the surrender Japan still had 2,000,000 men under arms in the homeland and was capable of conducting a tenacious ground defense; about 3,000 Japanese aircraft were also operational. Nevertheless, the Japanese could hardly have continued the war for more than a few months. On the other hand, the fact that an invasion was not necessary certainly spared many American lives.
The great arbiter of the Pacific war had been American industrial power, which produced a mighty war machine. Out of this production had come the Pacific Fleet, a potent force that could overcome the vast reaches of the Pacific upon which the Japanese had depended so heavily as a defensive advantage. The decisive combat element of the fleet was the fast carrier task force, which carried the war deep into Japanese territory and supported advances far beyond the range of land-based aircraft. Land-based air power also played a decisive part. When carriers were not available to support offensives, it was land-based aviation that measured the distance of each forward move. Land-based aviation proved important as well in providing close support for ground operations, while aerial supply operations and troop movements contributed greatly to the success of the Allied campaigns.
Both naval and air forces were dependent upon shore bases, and the war in the Pacific demonstrated that even in a predominantly naval-air theater, ground combat forces are an essential part of the offensive team. The Japanese had also been dependent upon far-flung bases, so that much of the Allied effort during the war had gone into the seizure or neutralization of Japan's bases. Thus, the Pacific war was in large measure a war for bases. On the other hand, the U.S. Pacific Fleet, in one of the greatest logistical developments of the war, went far in the direction of carrying its bases with it by organizing fleet trains of support vessels that were capable of maintaining the fleet at sea over extended periods.
Another important facet of the Pacific war was the development and employment of amphibious assault techniques, repeatedly demonstrating the need for unified command. Air, ground, and naval teamwork, supremely important in the struggle against Japan, occasionally broke down, but the success of the Allied campaigns illustrates that all three elements achieved it to a large degree. Strategic air bombardment in the Pacific, designed to cripple Japan's industrial capacity, did not get under way until well along in 1945. The damage inflicted on Japanese cities was enormous, but the effect, as in the case of the bomber offensive against Germany, remains unsettled, though the bombardment finally brought home to the Japanese people that the war was lost. The submarine played a vital role in reducing Japan's capabilities by taking a huge toll of Japanese shipping and by helping to cut Japan off from the resources of Southeast Asia.
In the final analysis Japan lost because the country did not have the means to fight a total war against the combination of industrial, air, naval, and human resources represented by the United States and its Allies. Admiral Isoroku Yamamoto, commander of the Japanese Fleet at the outbreak of the war, put his finger on the fatal weakness of the Japanese concept of the war, when he stated: "It is not enough that we should take Guam and the Philippines, or even Hawaii and San Francisco. We should have to march into Washington and sign the treaty in the White House." This the Japanese could never do, and because they could not they had to lose the war.