The Conquering Tide is the second installment of military historian Ian Toll's projected three-volume history of the Pacific War (1941–45). Volume 1, Pacific Crucible: War at Sea in the Pacific, 1941–1942, appeared in 2012.[1] The present work concerns the pivotal years from the "Operation Watchtower" landings on Guadalcanal (Aug. 1942) to the battle for Saipan (June–July 1944). It contains fourteen chapters plus an epilogue and is enriched by seventeen helpful maps tracing the stages of the Pacific War, plentiful photographs and endnotes, a bibliography, and a thorough index.[2]

A principal figure in Toll's story of the war is Adm. Ernest King, "the relatively obscure wartime leader of the United States Navy, who insisted on an early Pacific counteroffensive over the objections of virtually everyone that mattered" (xiii). Toll observes that the tendency of most historians to overemphasize land campaigns impedes a truly accurate understanding of the Pacific War as a whole. The Americans' strategic challenge after 1941 was to destroy the Imperial Japanese Navy (IJN), something they could achieve only through both naval and air power. Hence, naval operations belong "at the narrative spine of any history of the Pacific War" (xiv) and King, as both Commander in Chief of the US Fleet and Chief of Naval Operations, stands at the center of that narrative. Though King accepted President Franklin Roosevelt's Germany-first war policy, he insisted that adequate sea and land forces be committed to the Pacific theater; he also espoused aggressive offensive operations from bases in the New Hebrides, the Solomons, and the Bismarck Archipelago to counter Japanese strategy. The Joint Chiefs of Staff (over the objections of Gen. Douglas MacArthur) endorsed these strategic initiatives, one of which involved amphibious assaults on Guadalcanal and Tulagi in the Solomon Islands. Many similar operations were to come.

In the long term, the captured islands provided vital staging posts, complete with airfields, naval bases, and supply depots, to support further actions that would place Allied forces within striking distance of Japan's home islands. But actually taking Guadalcanal required landing newly enlisted marines with no training or experience in amphibious operations and sustaining them as they took control of the island in the face of fierce Japanese counterattacks. Until the United States ramped up its war production, such operations required the navy to buttress the troops on land while avoiding a decisive battle with the IJN. King was lucky to have senior admirals like Chester Nimitz, head of the Pacific fleet, and Raymond Spruance, Nimitz's chief-of-staff and later commander of the US Fifth Fleet. Both men were cool under stress and nicely balanced King's aggressiveness with the caution dictated by the tenuous position of the Navy in the Western Pacific at the time (296–300).

Vice Adm. Frank Fletcher, commander of the naval force at Guadalcanal, had to preserve his aircraft carriers against the predations of superior Japanese forces, while yet supporting US troops on the island. At the Battle of Savo Island (9 Aug. 1942), seven IJN cruisers sank three USN and one Royal Australian Navy cruisers in a skillful night action, killing 1,270 Allied sailors. Toll agrees with John Lundstrom[3] that Fletcher's notorious withdrawal of his carriers, leaving the men on Guadalcanal temporarily without air cover, was in fact well-advised, given his overall operational priorities:

American carrier-borne aircraft and their pilots were crucial to shifting the balance of power in the Pacific. In the first four carrier battles of the war—Coral Sea, Midway, Eastern Solomons, Santa Cruz—the Americans killed more than four hundred IJN airmen, "more than half the number that had been on active duty at the start of the war" (154).

Although Japanese airmen were as susceptible to fatigue as their adversaries, veteran pilots were not systematically rotated out of combat. Thus the pool of experienced pilots shrank faster than replacement personnel could be trained.[4] Additionally, as the war ground on, improvements in aircraft design and ramped-up production numbers finally gave USN pilots the tools they needed to definitively defeat Japanese naval air power (156, 423–27, 430). The Mitsubishi A6M "Zero" fighter no longer ruled the skies of the Pacific.

Among the USN's key assets was its increasingly lethal submarine fleet, which helped cut off Japan from the resources of the Pacific empire its army and navy had carved out earlier in the war. Inexplicably, the Japanese never bothered to develop state-of-the-art antisubmarine capabilities (282–83). The USN's Gato-class submarines were able to patrol sea-lanes for six to ten weeks at a time. By the end of the war, submarines were degrading IJN assets as much as aircraft carriers; but their devastation of enemy merchant shipping made a far greater contribution to ultimate US victory in the Pacific (254).

In the meantime, assaults against Japanese defensive forces on Tarawa and other islands taught American forces hard lessons about the value of interservice coordination and the logistics of amphibious operations. While army tactical doctrine stressed gradually taking ground with the support of massed artillery bombardment, the marines preferred more aggressive (and more costly) assaults to force rapid decisions against unprepared enemies. This jibed with the whole spirit of Admiral King's Pacific counteroffensive, but it had its perils. Not only had the navy's fire support at Tarawa been too brief to soften all the Japanese defensive positions before the marines landed, but poor knowledge of tidal depths and exposure to flanking fire decimated the landing craft and amphibious tanks hung up on offshore reefs. Nonetheless, Toll notes, "if the Americans had not made those mistakes at Tarawa, they would have made them in the Marshalls, suffering proportionally higher casualties as a result" (367). In the event, Tarawa prompted (American) life-sparing changes in the planning, preparation, and execution of amphibious operations against bigger targets like Saipan, where seventy-one thousand American troops fought thirty-two thousand Japanese defenders (462–508).

Tarawa and Saipan demonstrated the superiority of American strength, which could not be brought fully to bear in the opening months of the Pacific War. In this regard, the war comprised two distinct phases:

At the Battle of the Philippine Sea (19–20 June 1944), later dubbed the "Marianas Turkey Shoot," IJN commanders risked and sustained a debilitating defeat even as the battle for Saipan raged on (477–97). Scarcely three miles from Saipan lay the island of Tinian, whence the Enola Gay departed for Hiroshima in August 1945.