This book, a model of well researched scholarly writing, explains why Japan's early conquests in the Pacific theater of the Second World War were so much more fragile than those of its Axis ally, Germany, in the European theater. Author Lt. Col. Sean Judge was a career officer in the US Air Force from 1993 until his death due to cancer in 2012. The Turn of the Tide in the Pacific War was originally his doctoral dissertation in military history, directed by John Guilmartin at Ohio State University. The book contains eight chapters plus an introduction and conclusion.[1]

Judge identifies the key factor in the course of the Pacific War as strategic initiative: "the ability to influence the course of the conflict by being able to choose to wage those battles, operations, and campaigns most suited to the accomplishment of one's own political ends while avoiding those detrimental to the same" (16). He cites five factors as critical to the attainment of initiative in war: resources, intelligence, strategic acumen, combat effectiveness, and chance—all of the them governed by the political will behind them.

Judge clarifies how the Allies capitalized on their limited resources and effective intelligence to gradually establish initiative and then offensive capacity after the Pearl Harbor attack and Japan's lightning campaign of conquest across the West and South Pacific. He points out that, even in its season of triumph, Japan was plagued by critical weaknesses. For one, it was fighting alone, since the Axis powers achieved little coordination between the European and Pacific theaters, by contrast to the Allies' increasing coordination of efforts.

In his treatment of national command structures (chaps. 3–4), the author highlights the drawbacks of Japan's incoherent strategic planning (24–43). Specifically, the Imperial Japanese Army (IJA) dominated Japan's military establishment and the political cabinet at a time when the Imperial Japanese Navy (IJN) was becoming indispensable to the conduct of a war against the combined naval assets of the British Empire, Australia, and the United States.[2] Japan's national military apparatus was beyond its government's control and coordination between its army and navy had been deficient at the best of times. The Imperial General Headquarters could formulate strategy, but individual commands "had to negotiate local interservice agreements during the execution of operations in their areas. No overall area commander could force unity of effort based on his position" (33). This had dire implications for Japan's prospects even early in the Pacific War:

The rifts within Japan's command structure might have been mitigated and eventually overcome, had its army and navy shared a common perception of the war. But, as Judge stresses, Japan's disjointed and outdated intelligence system provided no clear view of what might lie ahead after Pearl Harbor. This intelligence blindness was reflected in Japan's ill-advised drive southward toward Papua New Guinea and Australia and the failure of its naval operations in the Aleutians and at Midway (44–75).

By contrast, the Allies benefited by their close intelligence cooperation both among themselves and within their respective service branches. Moreover, the deployment of the US Marine Corps, a land force, required that Allied naval intelligence devote its efforts toward analyzing Japanese forces on both land and sea. Hence, coastwatchers on islands across the South Pacific, radio intelligence analysts, and codebreakers gave the Allies decisively better "situational awareness" in the weeks before the battles of Coral Sea and Midway (76–104). This advantage permitted the Allies, especially the US Navy under admirals Ernest King and Chester Nimitz, to engage the enemy under favorable circumstances, even though Japanese strength in the Pacific was greater. The Navy could commit resources and calculate risks based on extensive knowledge of Japanese capabilities and intentions. This was an impressive achievement, given the US adherence to a "Germany First" policy.

The Battle of the Coral Sea (3–8 May 1942) broke a string of Japanese naval victories and allowed US carrier aircraft pilots to hone their skills in attacking enemy ships and planes. Although the Americans suffered grievous losses—USS Lexington was sunk and Yorktown damaged—Japan was forced to cancel a combined-operations attack against Port Moresby in Papua New Guinea (130–31). Only a month later, superior situational awareness was a key factor in Admiral Nimitz's orchestration of an ambush against a Japanese carrier task force moving against Midway:

Coral Sea and Midway[3] inflicted such colossal material and psychological damage on the IJN that the United States and its allies were able to take the offensive in Papua New Guinea and Guadalcanal against an enemy still materially superior. Deploying land and sea assets to Guadalcanal committed the Americans to an operation far distant from Hawaii or the US mainland at a time when they lacked the logistical capacities and overwhelming material edge that ultimately ensured their crushing victory over Japan.

At Guadalcanal, the IJN deployed fast, powerful destroyers and cruisers with excellent night optics and Long Lance torpedoes that outperformed Allied models. Among other things, the Americans' inept use of radar gave the IJN a lopsided victory at Savo Island. This setback might well have imperiled the Guadalcanal campaign if the Japanese cruisers had pressed their advantage and attacked the US supply vessels supporting the troops on shore (168–69). Chance, in the person of a timid Japanese commander,[4] spared the Americans a disaster.

So the gamble paid off: American intelligence yielded enlightened strategical calculations[5] that bore fruit at Midway, where American admirals could confidently commit their ships, aircraft, and men, while US pilots showed extraordinary courage in pressing the attack. By shattering the Japanese initiative at Midway, "the Allies achieved the freedom of action" (202–3) to conceive and execute pivotal campaigns in New Guinea and on Guadalcanal.

Judge concludes by stressing that Pres. Franklin Roosevelt's dogged insistence on a Germany first policy made the Pacific a secondary theater of the global conflict. Had he allocated more personnel and matériel to the struggle against Japan, "the precarious Allied resource situation in the South Pacific could have been significantly eased" (203). On this point, Judge is quite right. But his discerning analyses make one wonder whether less was not more in the Pacific conflict in 1942–43, so that the Allies made a near perfect application of limited means to deliver a profound material and moral shock to their adversary. Sadly, it will not be the author of this fine, compelling study who gives us a sequel addressing that question.