United States Strategy - The Pacific War 1942 - History - Adventure Kokoda
The Pacific War 1942
The Pacific War 1942
The United States Strategy
When Japan launched its treacherous surprise attack on the United States Pacific Fleet at Pearl Harbor in Hawaii on 7 December 1941, and seized American island bases between Hawaii and the Philippines (Guam and Wake), one major aim was to facilitate capture of the Philippines without interference from the United States Navy. As starving American and Philippine troops fought a hopeless battle against invading Japanese troops between December 1941 and May 1942, any hope of reinforcement by the greatly weakened United States Pacific Fleet was negated by the Japanese Navy's control of the vast stretch of water between Hawaii and the Philippines. To appreciate the major contribution by General Douglas MacArthur to the American military disaster in the Philippines, see Battle of the Philippines.
Admiral King refused to accept the largely defensive role assigned to the US Navy in the Pacific War theatre by Winston Churchill and President Roosevelt. With the warships that were left to him after the treacherous Japanese attack on Pearl Harbor, he went on the offensive against Japan and almost certainly saved Australia and Hawaii from Japanese occupation in 1942.
Pearl Harbor found the United States with a mostly obsolete Navy
At the time of Pearl Harbor, the warships of the United States Navy were mostly elderly relics dating back to the World War I era and earlier. This situation had been brought about by two decades of isolationism and neglect of the Navy by the US Congress and Administrations before that of President Franklin D. Roosevelt. An exception to this neglect of America’s defences was the Pacific Fleet’s force of four large fleet carriers. Each of these carriers was equal to any of Japan’s six largest fleet carriers. The major difference between the American and Japanese carriers lay in the quality of the aircraft and the experience of the aircrews. The aircraft on the American carriers were either obsolete or nearing obsolescence. Most of the American aircrews lacked any combat experience, and many were under-trained. The Japanese naval airmen had been honing their combat skills in Japan’s brutal war against China since 1937.
Within the limitations imposed by the Washington and London Naval Treaties, Japan had built the most powerful navy in the Pacific region at the time of Pearl Harbor. To match the power of the Imperial Japanese Navy in early 1942, the US Navy needed to be provided with a large fleet of modern warships, especially fast and powerful aircraft carriers. Apart from the four large aircraft carriers that had escaped the deadly Japanese onslaught at Pearl Harbor, and the addition of USS Hornet in February 1942, that modern fleet still had to be built in American shipyards that were struggling at the time of Pearl Harbor to meet the demands of the Battle of the Atlantic. American shipbuilding capability had been seriously impaired during the Great Depression years (1929-1939) when many American shipyards had been forced to close their gates.
The problem facing Americans after Pearl Harbor was the lead time necessary to build a large warship and prepare it for battle. Under pressure of war, the time between the laying of the keel of a large carrier and achieving operational status was reduced to two years. The first of the powerful Essex Class carriers was laid down in April 1941. USS Essex (CV-9) became fully operational in June 1943. It was joined by the second Essex Class carrier Yorktown (CV-10) in December 1943. These inescapable timings meant that between Pearl Harbor and the middle of 1943, the United States had only four of the large carriers mentioned above to keep the powerful Japanese Navy at bay across the vastness of the Pacific. USS Saratoga (CV-3) was torpedoed twice during 1942, and was out of action for most of that critical year.
Japan’s attack on Pearl Harbor would transform American Pacific war strategy, naval tactics, and senior naval command.
President Roosevelt is persuaded to adopt a "Germany First" war strategy
Less than two weeks after he won an unprecedented third term in office in November 1940, President Roosevelt received a private briefing from the Chief of Naval Operations, Admiral Harold R. Stark. Stark warned Roosevelt that failure by the United States to aid Britain against Germany would almost certainly lead to Britain's defeat and German domination of the whole of Europe, the Middle East and Africa. Stark argued that American aid to Britain should include actual participation in the war in Europe and North Africa by US armed forces. Stark also argued that top priority should be given to defeating Germany regardless of any threat that might arise from Japan.
Admiral Stark's advice that the defeat of Nazi Germany should be the top priority of the United States even in the event of war with Japan was accepted by President Roosevelt, and formally designated as "Plan D". The plan acquired the designation "D" simply because it followed the numbering in Stark's formal memorandum to the President. However, Plan D was effectively an implementation of the American military’s Rainbow -5 strategic war plan. Rainbow -5 stipulated as its premise that the United States was engaged in war against the three Axis powers, Japan, Germany and Italy. This plan specified that American military power would be deployed against Germany and Italy as a priority even if Japan had already entered the war as their ally. Until Germany and Italy were defeated, Rainbow -5 required the United States to adopt a defensive posture in the Pacific behind lines linking Hawaii to Alaska and Panama. The Rainbow -5 war plan clearly involved abandoning everything west of Hawaii to the Japanese, including the Philippines and Australia.
The US Army Chief of Staff, General George C. Marshall, supported Plan D and President Roosevelt authorized talks between the American and British military chiefs of staff to implement Plan D. In March 1941, the American and British chiefs of staff met secretly and agreed that the Americans would join Britain in pursuing a "Germany First" war strategy if the United States was drawn into World War II as an ally of Britain.
The "Germany First" war strategy was not announced to the American public for a number of reasons. One compelling reason for secrecy was the fact that the United States was not yet at war with Germany. There would also have been major political risks for Roosevelt in disclosing the proposed war strategy. Apart from attracting the fury of the powerful isolationist and peace lobbies, it would have been an admission that America's army in the Philippines would be abandoned to its fate in the event of a Japanese attack.
The Arcadia Conference confirms a "Germany First" Allied war strategy
As the United States increased its military support for Britain during 1941, the British Prime Minister Winston Churchill foresaw the probability that the Americans would be drawn into the conflict with Germany and Italy as an ally of Britain. In that event, Churchill strongly supported adoption by the Anglo-American Allies of a "Germany First" war strategy. Churchill appreciated that this war strategy would put Australia, British Malaya, the Philippines, and the rest of South-East Asia at serious risk of Japanese occupation if Japan entered the war on the side of Germany and Italy. However, this prospect does not appear to have greatly concerned Churchill whose top war priorities were the defence of Britain, Egypt, Palestine, the Suez Canal, and India.
The top war priorities for British Prime Minister Winston Curchill were the defence of Britain, Egypt, Palestine, the Suez Canal and India. He argued strongly for the United States and Britain to pursue a "Germany First" war strategy and treat the Pacific as a secondary theatre of World War II. Churchill does not appear to have been greatly concerned by the Japanese threat to invade Australia.
As Churchill saw it, the Philippines, Australia, British Malaya, and the Dutch East Indies could be recovered from Japanese occupation after Germany had been defeated.
The treacherous Japanese surprise attack on Pearl Harbor both delighted and worried Churchill. He knew that the United States would now be fighting the Axis powers with Britain, but he was concerned that President Roosevelt would be unable to resist public pressure to exact vengeance for Pearl Harbor. Just before Christmas 1941, the British Prime Minister and his military chiefs travelled to Washington aboard the battleship HMS Duke of York to consult with President Roosevelt and his military chiefs. The purpose of this journey was to persuade Roosevelt to adhere to the secret agreement between the American and British governments to give priority to defeating Nazi Germany, and not to divert America's vast resources to halting Japanese aggression in the Pacific. This meeting of the two leaders and their military chiefs became known as the Arcadia Conference.
Churchill was alarmed to find on his arrival in Washington that the American public and Congress were calling for an all-out war of vengeance against Japan. The American people were still unaware that their President and his military chiefs had secretly committed the United States to defeating Germany as its top priority, and that this agreement meant holding a defensive line between Alaska, Hawaii, and the Panama Canal. They were also unaware that the "Germany First" war plan effectively made everything west of that line expendable, including Australia and American military forces in the western Pacific.
When Roosevelt and Churchill joined the American military chiefs in conference on 23 December 1941, Admiral Stark had been replaced as chief of the US Navy. The new Commander in Chief of the US Navy was Admiral Ernest J. King, and he was strongly opposed to any downgrading of the war against Japan to a secondary theatre. The US Army Chief of Staff, General George C. Marshall, was conscious of the fact that his army troops would have a much larger role to play in an assault on the Nazi stronghold of occupied Europe and he supported the "Germany First" strategy. With nearly two million American recruits in the US Army, and his troops heavily under-employed at that moment, Marshall was keen for the assault on Nazi-occupied Europe to be undertaken as quickly as possible.
Churchill dismissed the feasibility of an early invasion of Europe. He pointed out that the Allied forces were simply not trained, equipped, and ready to invade Nazi-occupied France. Churchill argued forcefully that American troops would be better employed in a lower scale invasion of North Africa to assist British and Australian troops to defeat General Erwin Rommel's Afrika Korps. Having been the architect of disastrous amphibious landings in World War I (Galipolli) and World War II (Narvik), Churchill knew better than Marshall the grave dangers inherent in putting inexperienced troops ashore on a strongly defended coast. Churchill had assigned the code-name "Gymnast" to his plan for American army troops to gain amphibious landing experience in North Africa, before they undertook the far more dangerous task of assaulting the strongly defended coast of Nazi-occupied France.
To the dismay of the American military chiefs, President Roosevelt supported Churchill. Roosevelt underlined the political necessity of bringing the rapidly expanding American recruit army into action as soon as possible, and agreed that the North African operation was appropriate for that purpose. The American landing in North Africa was fixed for November 1942. It would later become known as "Operation Torch".
Roosevelt maintains the secrecy of the "Germany First" war strategy
Although conscious of the political risks for his Democratic Party in adhering to the "Germany First" war strategy so soon after Pearl Harbor, Roosevelt was persuaded by Churchill to adhere to this plan and it was confirmed in writing at the Arcadia Conference. Appreciating that the American public and Congress would not tolerate a war strategy that allowed the Japanese to proceed on an unchecked rampage across the Pacific, President Roosevelt decided to keep secret his government’s commitment to the "Germany First" war strategy.
The United States establishes a military command in Australia
Despite committing the United States to defeating Nazi Germany as its top priority, Roosevelt appreciated that the inevitability of American defeat in the Philippines made it important for the United States to hold Australia and the string of islands between Australia and Hawaii as bases for an eventual American counter-offensive against Japan. During the Battle of the Philippines , the United States Army established a new command in Australia on 22 December 1941. The new command was based at Brisbane and designated the US Army Forces in Australia (USAFIA).
The commander of USAFIA was Major General George Brett, and he was answerable to General MacArthur who was still at that time the commander of the American army in the Philippines. The purpose of USAFIA was initially to channel military supplies to the Philippines. However, the Japanese overran South-East Asia so quickly that few supplies reached the beleaguered American army in the Philippines except by submarine. Although circumstances prevented USAFIA making a significant contribution to the defence of the Philippines, the American government appreciated the importance of building up American military strength in Australia which was intended to be the main base for an Allied counter-offensive against Japan’s southern defensive perimeter which was anchored on the port of Rabaul in New Guinea after 23 January 1942.
Admiral King refuses to accept a defensive role for the US Navy in the Pacific
Admiral Ernest J. King was appointed Commander in Chief of the United States Navy (COMINCH) in mid-December 1941, and he replaced the more cautious, Europe-centred Admiral Harold R. Stark. The man chosen by President Roosevelt to slow the Japanese rampage across the Pacific was an unlikely choice of commander to undertake a purely defensive function. King was a brilliant, tough and aggressive naval officer.
Franklin D. Roosevelt
President Roosevelt initially supported aggressive action by Admiral Ernest J. King to halt the Japanese rampage in the Pacific and save Australia from invasion. When Admiral King's counter-offensive against Japan was opposed by the US Army Chief of Staff, General George C. Marshall, in April 1942 on the ground that it breached the agreed Allied "Germany First" war plan, Roosevelt cut military support for the Pacific theatre. Admiral King refused to accept the largely defensive posture assigned to the US Navy in the Pacific and went on the offensive with the ships that had survived Japan's treacherous attack on the Pacific Fleet at Pearl Harbor.
When Admiral King assumed command of the US Navy, he found that Stark had been prepared to sacrifice everything west of the International Dateline to the Japanese, including Australia and the American army in the Philippines. Admiral King rejected Stark’s approach. He believed that the United States would need access to Australia as a major base for a counter-offensive to recover the Philippines from Japan. He refused to adopt a defensive posture while the United States rebuilt its fleet.
Admiral King attended the Arcadia Conference and although he agreed in principle with Churchill’s "Germany First" war strategy, he insisted that the vaguely worded Arcadia agreement include words that would permit the United States to defend positions in the Pacific that were deemed necessary "to safeguard vital interests". The words "vital interests" were not defined, and King argued successfully for inclusion in the agreement of words authorizing the seizure of "vantage points" from which a counter-offensive against Japan could be developed.
The Arcadia Conference ended with Churchill and the US Army believing that the United States would pursue a war strategy that placed priority on defeating Germany and relegated the Pacific to a secondary theatre in which the United States would pursue a passive defensive posture until such time as Germany had been defeated. The US Army position was largely motivated by self-interest. The generals knew that there would be little employment for two million under-trained American soldiers in the difficult island fighting that characterized the Pacific War. The only place to deploy an army of two million recruits was on the continent of Europe, and the American generals were determined to send them there.
The US Navy was well satisfied with the final wording of the Arcadia agreement. Churchill may not have realized it, but Admiral King was determined to prevent Australia becoming part of the Japanese empire and to secure the lines of communication between Australia and the United States. The Pacific Fleet had been savaged by the treacherous Japanese surprise attack on Pearl Harbor, but the four American fleet carriers had survived. Admiral King had been authorized by Arcadia to "safeguard vital interests" and seize "vantage points" in the Pacific from which a counter-offensive against Japan could be developed. King interpreted the wording of the Arcadia agreement as allowing him to go on the offensive against Japan with the limited naval resources available to him.
When Admiral Chester W. Nimitz replaced Admiral Husband Kimmel as Commander in Chief Pacific Fleet (CINCPAC) on 31 December 1941, he found new orders from Admiral King. Nimitz was ordered to defend vital military areas, halt the Japanese advance, keep the lines of communication with Australia open, and mount offensives against the Japanese with his three aircraft carriers USS Enterprise, Lexington and Saratoga and other warships available to him in the Pacific. King ordered the return of aircraft carrier USS Yorktown to the Pacific after a stint of convoy duty in the Atlantic.
The US Navy and Army disagree over allocation of American military resources
During the early months of 1942, fierce debate ensued between the US Navy and Army as to where America’s then limited military resources of shipping, trained troops, and equipment should be allocated. Following the Churchill line, the US Army rated the European theatre, the Middle East, and India as being America’s top war priorities. Although the US Army rated the keeping open of lines of communication with Australia as being "highly desirable", and was prepared to allocate under-trained garrison troops for that purpose, it consistently opposed allocation of significant numbers of Army aircraft and its best troops to the South Pacific theatre.
As the Japanese rapidly tightened their grip on South-East Asia and threatened Australia, Admiral King moved quickly to establish garrisons on islands that would provide Allied staging and defensive strongholds between Hawaii and Australia. He rushed a US Marine brigade to the South Pacific to provide a garrison for American Samoa. Rather than endure the embarrassment of allowing huge numbers of American army reservists and recruits to remain idle in the United States, the US Army provided small garrisons for America’s Palmyra, Canton, and Christmas Islands. The US Navy then established a refueling base at Bora Bora in the French Society Islands.
The strategic importance of New Caledonia, as a rich source of the minerals nickel and chrome, persuaded the US Army to cobble together an improvised Americal division of 15,000 infantry supported by tanks, artillery and a fighter squadron as a garrison for that island. Technicians, engineers, and fuel supplies were also rushed to each of these island staging posts between Hawaii and Australia. The US Army components of these South Pacific island garrisons were mostly drawn from under-trained Army Reservists, National Guards, and raw recruits.
Admiral King establishes an ANZAC Command for the defence of Australia
The squabbling between the US Navy and Army over allocation of resources to the South Pacific was interrupted by the extension of Japanese military aggression to Australian New Guinea with the capture of Rabaul on 23 January 1942. Admiral King responded quickly to the developing Japanese threat to Australia by appointing Rear Admiral Herbert F. Leary commander of a new ANZAC Area with responsibility to protect Australia and New Zealand from the advancing Japanese. King also dispatched the carrier USS Lexington to patrol the seas north of Australia.
The US accepts responsibility for the defence of Australia against Japan
Following the capture of Rabaul, British intelligence predicted, correctly as it turned out, that Japan's next move would be to capture the Solomon islands, New Caledonia and the Fiji Islands. The Japanese assigned the code reference "Operation FS" to this plan which was intended to cut the lines of communication between Australia and the United States.
With the capture of Rabaul, the Japanese were not merely on Australia's doorstep but already had one foot through the front door. The only troops available in Australia to defend it from invasion were 265,000 undertrained and poorly equipped militia recruits. Three of Australia's four well trained and equipped AIF divisions had answered Britain's call and had been sent to the Middle East. The fourth division (8th AIF Division) was scattered across Australia's northern approaches at Singapore, Timor, Ambon, and Rabaul.
Responding to the grave threat of Japanese invasion, Prime Minister Curtin called for the return of two Australian AIF divisions from the Middle East to defend their own country. Curtin’s request cut squarely across British-American war strategy that gave priority to defending the Middle East and India. Winston Churchill was very reluctant to see two battle-toughened Australian divisions released to defend their own country when he wanted to employ them in the defence of India. The British Prime Minister felt obliged to ask President Roosevelt to provide American troops for the defence of Australia. Roosevelt agreed, and on 15 February 1942, he announced that the United States would accept responsibility for the defence of Australia and New Zealand. Pursuant to that undertaking, a forward echelon of the US 41st Infantry Division embarked for Australia on 4 March 1942, and arrived in Sydney on 7 April 1942. On 22 April 1942, the 32nd Infantry Division sailed from San Francisco for Australia and arrived at Adelaide on 14 May 1942. Although welcomed by the Australian government, these American divisions were composed of under-trained and inexperienced National Guard units.
The US Army opposes Admiral King’s plans to go on the offensive against Japan
The Allies were stunned by the fall of Britain’s much vaunted "impregnable fortress" Singapore to the Japanese on 15 February 1942. On 18 February 1942, Admiral King proposed to his army counterpart General Marshall establishment of naval facilities at Tongatapu in the Friendly Islands, and establishment of army garrisons at Tongatapu and Efate in the New Hebrides. Marshall balked at this proposal. He suspected that King was preparing for a major offensive against the Japanese in the South Pacific in defiance of the agreed "Germany First" war strategy, and requested clarification of the purpose of establishing American bases so far west of Hawaii. King responded in a memorandum dated 2 March 1942. The Navy chief admitted that his purposes in establishing the two bases were not only to protect the lines of communication with Australia but also to establish bases from which a step-by-step advance could be mounted through the Solomons to the Bismark Archipelago situated off the north-eastern coast of the New Guinea mainland. King pointed out that such an advance against Japan’s southern defensive perimeter would be likely to deflect the Japanese advance towards Australia and draw Japanese troops away from Burma.
President Roosevelt appears to support Admiral King’s aggressive Pacific War strategy
The disagreement between his senior Navy and Army commanders caused President Roosevelt to convene a meeting of the Joint Chiefs of Staff on 5 March to discuss Pacific strategy.
Predictably, the Army chiefs argued that Admiral King’s Pacific strategy would undermine the "Germany First" commitment. King summarized his proposal as being to hold Hawaii, support Australia, and drive deeply into Japan’s southern defensive perimeter through the Solomon Islands.
President Roosevelt was keenly aware that, after Pearl Harbor, the American people and Congress were in no mood to tolerate inaction by his government in the face of continuing rapid Japanese military advances in the South Pacific. Affirming the need to defend Australia, the President appeared to give his support to Admiral King’s aggressive Pacific strategy.
The US Navy develops a war strategy for the Pacific War
Admiral King now felt that he had backing from Roosevelt to go on the offensive against Japan, and he passed his plan for development to Rear Admiral Richmond K. Turner, chief of the War Plans Division in Washington. Turner presented his "Pacific War Campaign Plan" to Admiral King on 16 April 1942. The Pacific War plan involved a basic premise that it would be much more difficult for the United States to recover territory after it had been captured by the Japanese and fortified. Turner argued that the Japanese should be prevented from occupying areas that the US Navy viewed as being vital for mounting a successful American-Australian counter-offensive. Turner included in those areas Australia, Port Moresby on the southern coast of the New Guinea mainland, the Solomon Islands to the east of New Guinea, and the string of islands between the Solomons and Hawaii.
The Turner Pacific War plan comprised four phases. The first phase required a build-up of American forces and positions in the South and South-West Pacific. The second phase was to be a combined American-Australian offensive through the Solomons and New Guinea to recapture the northern coast of New Guinea and the Bismark Archipelago where the Japanese were establishing a major base at the former Australian port of Rabaul.
The third phase involved the removal of the Marshall and Caroline Islands from Japanese control and establishment of advanced American air and naval bases on those island groups. This phase had been US Navy war strategy between the World Wars in the event of war with Japan, but the rapid Japanese advances across South-East Asia and deepening threat to Australia had forced priority to be given to mounting a counter-offensive through the Solomons and New Guinea.
The final phase would involve an Allied advance into the Netherlands East Indies or the Philippines, depending upon which of the two offered the greater strategic advantage to the Allies.
The Turner plan envisaged a step-by-step and simultaneous Allied counter-offensive through New Guinea and the Central Pacific island groups. Pacific islands would be used as stepping stones to reach the Philippines, and land-based aircraft would protect each advance. Retaining Allied control of Port Moresby was viewed as being vital to the success of the Allied counter-offensive.
Admiral King approved Rear Admiral Turner’s Pacific War plan, and it became the US Navy’s basic war strategy for the Pacific.
The US Army refuses to provide additional troops for a Pacific counter-offensive
Although Admiral King had the President’s verbal approval to pursue an aggressive Pacific war strategy, the US Army refused to provide additional troops beyond the 41,000 already committed to defend the lines of communication with Australia. The US Navy had already committed 15,000 of its own Marines.
On 9 March 1942, the American Joint Chiefs of Staff split the Pacific into the South-West Pacific Area (SWPA) and the Pacific Ocean Area (POA). The South-West Pacific Area comprised Australia, New Guinea, and the Philippines. General MacArthur would be rescued from his beleaguered army in the Philippines to take command of this new military area from Australia. SWPA was not viewed in Washington as a prestigious command. President Roosevelt was not an admirer of MacArthur’s leadership qualities, and he felt that MacArthur deserved a posting to a location that was viewed in Washington as one of the backwaters of World War II. The ANZAC Area was abolished and Rear Admiral Leary and his ships were placed under MacArthur’s control.
In addition to his command of the Pacific Fleet, Admiral Chester Nimitz was appointed Commander in Chief Pacific Ocean Area. Under the overall command of Nimitz, the Pacific was divided into North, Central, and South Pacific sub-commands. Nimitz retained direct operational command of the North and Central Pacific areas. Rear Admiral Robert L. Ghormley was appointed Commander South Pacific, and he was responsible to Nimitz.
The US Army persuades Roosevelt to deny additional resources for the Pacific
On 1 April 1942, the US Navy’s Pacific War plan received an unexpected setback. General Marshall complained to the President in what has become known as the Marshall Memorandum that diversion of military resources to the Pacific placed Britain and the Soviet Union at risk of defeat by Germany. Marshall called for a massive build-up in Britain of American troops and aircraft , code-named "Bolero", in preparation for a limited offensive in Nazi-occupied Europe in late 1942 to take pressure off the Soviet Union. Marshall also proposed a major invasion of Europe, set tentatively for April 1943. Churchill, with his own experience of disastrous landings at Gallipoli and Narvik, was appalled by the failure of the American army commanders to appreciate the grave dangers involved in putting inexperienced troops ashore on a strongly defended coast. He had warned Roosevelt and Marshall of these dangers on his visit to Washington in late December 1941, but Marshall had chosen to ignore Churchill’s advice.
In the first week of May 1942, President Roosevelt did an extraordinary backflip on US Pacific War policy. Perhaps influenced by very heavy American shipping losses from German U-boat activities in the Atlantic, Roosevelt reaffirmed priority for Churchill’s "Germany First" war strategy. By making this decision, Roosevelt effectively declared Port Moresby, the Australian mainland, Hawaii, and all of the island groups between them to be hostages to fortune. Denied significant military resources by Roosevelt from early May 1942, Admiral King would have to try to save Australia, Port Moresby, and Hawaii from Japanese attack and occupation with the meagre resources already available to him, including all that remained of his Pacific Fleet after the devastating Japanese sneak attack on Pearl Harbor.
Fortunately for Australia and Hawaii, the US Navy had in Admirals King and Nimitz two of the best commanders of World War II. King was a brilliant and bold strategist. Nimitz was a brilliant and bold tactician. Aided by Allied code-breaking skills, American heroism, and extraordinary good luck, these two admirals would save Roosevelt’s presidential reputation at the crucial Battle of Midway on 4 June 1942.
The apparently inexorable advance of Japanese military forces across the Pacific and South-East Asia forced President Roosevelt to replace senior American navy and army commanders in the Pacific region who had failed to heed warnings from Washington and take appropriate steps to meet the Japanese threat to their commands. The navy and army commanders at Pearl Harbor at the time of the Japanese attack were replaced. General Douglas MacArthur escaped dismissal because the full story of his incompetent defence of the Philippines was not revealed until after the war. The Chief of Naval Operations in Washington, Admiral Harold R. Stark, was replaced as Commander in Chief of the US Navy by Admiral Ernest J. King, a brilliant and aggressive strategist. Admiral King appointed Admiral Chester W. Nimitz as Commander-in-Chief of the Pacific Fleet in late December 1941.
Admiral King refused to accept the largely defensive role assigned to the United States Pacific Fleet by President Roosevelt and British Prime Minister Winston Churchill at the Arcadia Conference in late December 1941. King ordered Nimitz to defend vital military areas, halt the Japanese advance, keep the lines of communication with Australia open, and mount offensives against the Japanese with his three aircraft carriers USS Enterprise, Lexington, and Saratoga which had escaped the devastating Japanese attack on the American battleship fleet at Pearl Harbor.
Admiral King ordered the carrier USS Yorktown to cease convoy duty in the Atlantic and rejoin the Pacific Fleet. Yorktown arrived at San Diego on 30 December 1941. The return of Yorktown from the Atlantic was fortunate because Saratoga was hit by a submarine-launched Japanese torpedo south of Hawaii on 11 January 1942 and was unavailable for active service from that date until her return to Pearl Harbor on 6 June 1942.
American carriers raid Japanese military bases in the Pacific
Admiral Nimitz deployed his three aircraft carriers in a series of bold hit-and -run raids against Japanese military forces occupying islands on Japan's vastly expanded defensive perimeters in the Pacific Ocean.
The first American carrier raid was carried out by Enterprise and Yorktown against the Japanese-occupied Marshall and Gilbert Islands on I February 1942. Appalling weather conditions over these islands reduced the effectiveness of the raid, but this demonstration that the US Pacific Fleet was still in business caused concern in Tokyo.
On 14 February 1942, Vice Admiral William F. Halsey's carrier task force TF-8, centred on Enterprise, left Pearl Harbor to carry out hit-and-run raids on America's Wake Island, now occupied by Japanese invaders, and Japan's own Minami-tori Island (also known as Marcus Island), a coral atoll in the central Pacific only 1,000 miles (1,600 kilometres) south-east of Tokyo. The raid on Minami-tori Island produced alarm at the headquarters of the Japanese Navy's Combined Fleet because it was so close to Japan's four home islands.
The Japanese capture Rabaul
The port of Rabaul is situated on the island of New Britain which lies off the north-eastern coast of the New Guinea mainland. As early as August 1941, the Japanese had been planning to capture the town of Rabaul with its fine harbour. The inclusion of Rabaul in the First Operational Phase following the Japanese attack on Pearl Harbor was instigated by Vice Admiral Shigeyoshi Inoue, commander of Japan's 4th Fleet or South Seas Force. Rabaul was only 700 miles (1,125 km) to the south of Japan's major naval base at Truk in the Caroline Islands, and Inoue believed that the capture of Rabaul was essential to prevent Australia allowing its use by American B-17 heavy bombers to attack Truk. The Japanese also intended to turn Rabaul into their main base for further military operations in New Guinea and the Solomon Islands. On 23 January 1942, five thousand troops of Japan's elite South Seas Detachment stormed ashore at Rabaul. With control of the air and support from the guns of their own warships, the Japanese troops quickly overwhelmed the small and poorly equipped Australian garrison.
In response to the Japanese capture of Rabaul, Admiral Nimitz ordered Vice Admiral Wilson Brown to take Lexington and attack Japanese shipping and shore installations at Rabaul. A Japanese patrol plane detected the approach of the Lexington task force to Rabaul on 20 February 1942, and a formation of eighteen Mitsubishi G4M medium bombers (Allied code-name "Betty") was launched from Rabaul to attack the American carrier. Lexington's F4F Wildcat fighters of squadron VF-3 shot down sixteen of the Japanese bombers. Lexington was not damaged in the attack, but Admiral Brown felt it wise to withdraw now that the Japanese had been alerted to the presence of his carrier group.
The Japanese capture Lae and Salamaua
Having captured Rabaul, the Japanese soon found their new base being subjected to Allied air attacks launched from Lae and Salamaua on the north-eastern coast of the New Guinea mainland and from Port Moresby on the southern coast of the New Guinea mainland. Vice Admiral Inoue was able to persuade Japan's Naval General Staff that Rabaul had to be protected from Allied air raids by Japan occupying Lae, Salamaua, Port Moresby, and the island of Tulagi in the British Solomons. On 29 January 1942, the Commander-in-Chief of Japan's Combined Fleet, Admiral Isoroku Yamamoto, was ordered by Naval General Staff to capture Lae and Salamaua and, having done that, to capture Port Moresby and Tulagi.
The capture of Lae and Salamaua would not only eliminate two sources of Allied air raids on Rabaul but also provide the Japanese with forward airstrips from which their attack on Port Moresby could be supported. The capture of Port Moresby was an important aspect of the Japanese plan to sever communications between the United States and Australia. Port Moresby would provide the Japanese with a base from which they could launch bombing strikes deep into the Australian mainland and across the Coral Sea. It would enable the Japanese to block sea access to Australia's northern port of Darwin from the east. The Port Moresby operation was given the code reference "MO" and was fixed for April 1942.
Vice Admiral Brown's aborted carrier raid on Rabaul on 20 February caused the Japanese to postpone the capture of Lae and Salamaua until 8 March 1942. The postponement was deemed necessary to replace the large number of Japanese bombers destroyed by Lexington's fighters.
In the pre-dawn darkness of 8 March 1942, and screened by heavy monsoonal rain, Japanese troops began wading ashore from landing barges at the town of Lae and the nearby village of Salamaua. The landings by three thousand Japanese troops were not opposed by the small Australian garrisons which had already begun to withdraw to the small goldmining towns of Bulolo and Wau in the New Guinea highlands where strategically important airstrips were located.
American carriers strike the Japanese beachheads at Lae and Salamaua
While the Japanese were establishing their beachheads at Lae and Salamaua, Lexington and Yorktown were steaming across the Coral Sea with the intention of striking Rabaul. When he became aware from signal intercepts that Japanese landings were under way at Lae and Salamaua, Vice Admiral Brown quickly changed the objective of his raid. He knew that the Japanese would be highly vulnerable to attack while they were engaged in unloading troops and supplies from their invasion transports, so he diverted Lexington and Yorktown to the southern coast of New Guinea, and launched his air strike against the Japanese beachheads from the Gulf of Papua. Before dawn on the morning of 10 March 1942, one hundred and four aircraft from the two American carriers crossed the towering Owen Stanley Range and took the Japanese completely by surprise. For the loss of one American plane, this brilliantly planned and executed raid cost the Japanese four transports sunk, three warships severely damaged, and four other ships damaged. The Japanese commander's own flagship, the cruiser Yubari, received several bomb hits and had to return to Japan for repairs. It was a stunning demonstration to the Japanese that the United States Pacific Fleet was still a force to be reckoned with.
The American carrier raids cause the Japanese to review strategic priorities
For the Naval General Staff in Tokyo, the Lae-Salamaua raid reinforced its view that Japan's main strategic priority in the Pacific should be to cut the lines of communication between the United States and Australia. The Lae-Salamaua raid had demonstrated the urgent need for Japan to capture Port Moresby and Tulagi in the British Solomons as quickly as possible. On 15 March 1942, Japan's Imperial General Headquarters agreed with Naval General Staff that cutting the lines of communication between the United States and Australia was to be Japan's strategic priority in the Pacific and would commence with the capture of Port Moresby and Tulagi in April 1942.
The American carrier raids in the first three months of 1942 caused deep concern to Admiral Yamamoto. He was particularly concerned by Vice Admiral Halsey's raid on Minami-tori Island (Marcus Island) because this coral atoll was only 700 miles (1,125km) from Japan, and Yamamoto feared that the American carriers had the capability to raid Tokyo. Japan's military leaders had assured Emperor Hirohito that an American attack on Tokyo could never happen. To ensure the unthinkable did not happen, officers of Japan's Combined Fleet began to plan a complex operation to destroy the American Pacific Fleet at Midway in the central Pacific. The Midway plan would set the stage for disagreement as to Japan's strategic priorities in the Pacific between Naval General Staff and Combined Fleet. It would cause Japan to spread its military resources too thinly across the vast expanse of the Pacific Ocean.
The Lae-Salamaua raid causes revision of Japan's invasion timetables and lays the foundation for the Battle of the Coral Sea
Although not appreciated at the time by Admiral Nimitz, the Lae-Salamaua raid was of vital importance to the Allies for a number of reasons that would become apparent later in 1942. It was a severe blow to Japan's plan to isolate Australia from the United States as quickly as possible because the Japanese had intended to use the sunk and damaged transports as part of the invasion force to capture Port Moresby and Tulagi in April 1942. The Japanese were forced to postpone the capture of Port Moresby and Tulagi for one month to replace the sunk and damaged ships, and because Vice Admiral Inoue insisted that his operations to capture Port Moresby and Tulagi had to be supported by Japanese fleet aircraft carriers. Those carriers could not be made available for operations in the Coral Sea before May 1942. In this way, the Lae-Salamaua raid set the stage for the Battle of the Coral Sea in May 1942. The Battle of the Coral Sea laid the foundation for the American victory at the Battle of Midway.
The Lae-Salamaua raid lays the foundation for Allied victories at Guadalcanal and Kokoda
The Lae-Salamaua raid also laid the foundations for major Allied victories later in 1942 at Guadalcanal and Kokoda.
The capture of the island of Tulagi and its employment as a Japanese naval flying boat base was a preliminary to establishment of a Japanese forward airstrip a short distance away at Lunga Point on the northern coast of Guadalcanal. The one month delay in the capture of Tulagi produced by the Lae-Salamaua raid also delayed construction of the Japanese forward airstrip on Guadalcanal by at least one month. This delay provided the Americans with time to prepare a large landing force to capture the Japanese airstrip being built on Guadalcanal. Even so, the Americans barely reached Guadalcanal in time. When American Marines landed at Lunga Point on 7 August 1942, the Japanese were ready to bring into operation this airstrip that later became famous as Henderson Field. If the Americans had not seized this airstrip when they did, the Guadalcanal Campaign could not have proceeded as it did. An operational Japanese airstrip on Guadalcanal would have been a formidable obstacle to an American landing in 1942.
The Guadalcanal Campaign had a direct impact on the equally bloody fighting between the Japanese and Australians on the Kokoda Track. The Japanese outnumbered the Australians by five to one, were better armed and supplied, and had pushed the Australians slowly back across the Owen Stanley Range to the last ridge before Port Moresby. Although suffering terrible losses from Japanese mountain artillery, the Australians dug in to make a final stand. From the heights of the Owen Stanleys, the starving and exhausted men of Major General Horii's South Seas Detachment could actually see the searchlights sweeping the night sky at Port Moresby and the Japanese general begged for reinforcements for his final push to capture the vital Allied base.  Because of heavy Japanese losses at Guadalcanal, Major General Horii was denied reinforcements and he was forced to retreat to his beachheads with the Australians in hot pursuit.  If the Guadalcanal Campaign had not been initiated in August 1942, Horii would almost certainly have been reinforced and Port Moresby would have been lost to the Allies.
It will be apparent from the foregoing that the barely acknowledged Lae-Salamaua raid by Lexington and Yorktown produced consequences for the Pacific War out of all proportion to the damage inflicted on the Japanese by that raid.
Despite Japan's overwhelming superiority in warship numbers in early 1942, and the great distance to be covered by an American aircraft carrier force operating from Hawaii, there was justification for Admiral Yamamoto's concern that American aircraft carriers might breach Japan's eastern defensive perimeter and launch a retaliatory air strike on Japan. Within a month of the Japanese attack on Pearl Harbor, American strategists in Washington were planning a daring retaliatory aircraft carrier strike at Tokyo.
To reduce the risk to the American carriers, the bombers would have to be launched 500 miles (804 km) from Tokyo, and have the range to reach friendly forces in western China. Only land-based bombers of the American Army Air Corps could achieve such an operational range, and it was decided to use specially modified B-25 Mitchell medium bombers. Lieutenant Colonel James Doolittle was placed in command of this special bomber group, and after air crews had proved that they could take off in a distance equivalent to the flight deck of an aircraft carrier, sixteen B-25s were loaded aboard the aircraft carrier USS Hornet berthed at San Francisco.
On 2 April 1942, Hornet left San Francisco and set course for Japan with her flight deck crowded with B-25 bombers and her own aircraft stowed below on the hangar deck. North of the Midway Islands in the central Pacific, Hornet was joined by the carrier Enterprise which would provide fighter cover for the task force during the long voyage to Japan's home waters and supplement Hornet's own fighters on the return journey to Hawaii.
Early on the morning of 18 April 1942, when the American carrier force was still 700 miles (1,126 km) east of Tokyo, radar on the Enterprise detected one of the picket patrol boats manning Japan's eastern defensive perimeter. Although the Japanese picket boat was sunk by the cruiser USS Nashville, the commander of the carrier force, Vice Admiral William F. Halsey, could not ignore the possibility that a radio warning had been sent by the picket boat to Tokyo. Rather than increase the risk to America's vital carriers, Halsey decided to launch the B-25 bombers 150 miles (240 km) short of the planned launching point. This decision greatly reduced the prospect of the B-25s reaching friendly forces in western China, but Lieutenant Colonel Doolittle agreed with Halsey's decision.
USS Hornet launches B-25 bombers for the retaliatory Halsey-Doolittle Raid on Tokyo
Conditions were not good for launching heavily laden bombers from the deck of a carrier. Gale force winds lashed Hornet and churned up heavy seas which drenched deck crews as they readied the bombers for take-off. When all sixteen B-25s were airborne at 9.25 a.m. and heading for Japan, the American carriers and their escort warships turned and steamed back to Hawaii at top speed.
Thirteen of the B-25 bombers flew over Tokyo and dropped their bombs on oil storage facilities, factories, electricity generating plants, and military targets. The other three B-25s dropped their bombs over Yokohama, Nagoya and Kobe. All but one of the B-25s ran out of fuel before reaching friendly forces in western China and were forced to land in Japanese-occupied China. With the assistance of friendly Chinese farmers, seventy-one of the eighty airmen involved in the Doolittle raid reached free China. The vengeful Japanese rounded up and executed many of the Chinese civilians who had assisted the American airmen. Eight airmen were captured by the Japanese who executed four of them in retaliation for the raid. This grave war crime foreshadowed a frequent Japanese practice of executing captured Allied airmen throughout the Pacific War. The other four captives survived harsh imprisonment and were released at the end of the war. Lieutenant Colonel Doolittle survived the raid and rose to high rank in the Army Air Force.
Although physical damage to the Japanese cities was slight, the daring "hit and run" counter-attack stunned Japan. Japan's military leadership was humiliated by the Halsey-Doolittle raid because it had proved to be incapable of honouring its pledge to protect the safety of the emperor.
Although its tactical significance was slight, the Halsey-Doolittle raid had a profound influence on the outcome of the Pacific War. It threw Japan's strategic planning and priorities completely off balance. Prior to the raid, Japan's highest strategic priority in the Pacific had been to isolate Australia from her powerful ally, the United States, by seizing and fortifying a chain of islands between Hawaii and Australia. After the Halsey-Doolittle raid, defence of Japan's home islands from attack by the United States Navy would also be given the highest priority by Japan's military leadership.
The raid persuaded Japan's Imperial General Headquarters that Admiral Yamamoto's concern for the safety of Japan's home islands was well founded, and that it was necessary to extend Japan's eastern defensive perimeter closer to Hawaii by seizing and occupying America's Midway Islands in the central Pacific. Admiral Yamamoto had developed a complex plan for a Midway offensive in June 1942, coupled with a diversionary offensive against western islands of Alaska. Yamamoto's plan was designed to extend Japan's eastern defensive perimeter to the Midway Islands and draw the aircraft carriers of the United States Pacific Fleet to a decisive battle in the central Pacific. This plan was approved by Imperial General Headquarters which was confident that Japan's powerful navy could destroy the American carriers.
Japan had now committed itself to complex simultaneous military operations in the northern, central and southern Pacific in May and June 1942. Carried away by the euphoria produced by easy initial victories resulting from surprise attacks on British and American Pacific outposts, the Japanese military leadership had now made the fatal error of assuming that the United States Navy would adopt a largely defensive posture when confronted with further Japanese military aggression. This arrogant belief in Japan's invincibility, and underrating of American military capabilities and response, would be reflected in subsequent Japanese military planning, and ultimately lead to Japan's defeat.
Needless to say, after a series of military disasters following Pearl Harbor, the Halsey-Doolittle air raid on Japan provided a major boost to morale in the United States.
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