mikewint
Captain
A Japanese victory at Midway would certainly changed the manner in which WWII was waged by the US/Allied forces and beyond a doubt it would have lengthened the war but would not have changed the eventual outcome.
Consider that by June 1942, Oahu, was garrisoned by 100,000–150,000 soldiers. At the time of the Pearl Harbor attack the Japanese had estimated that they would need to deploy at least 45,000 men in the invasion of the Hawaiian Islands.
#1, that would be an invasion force 10 times larger than they had ever landed amphibiously at one time and
#2 was a serious underestimation of the manpower required for a successful invasion.
At the time of Midway the Japanese never seriously considered an invasion of the Hawaiian Islands
Returning to the loss of Midway, with the Japanese in control of the Island the August 1942 counteroffensive at Guadalcanal could not have occurred and the Japanese invasion of Australia and New Guinea could not have been stopped. In fact the entire South Pacific would have been open to Japanese invasion. The Japanese could have easily occupied the New Hebrides, Fiji, Samoa, and Tonga thus cutting the main line of supply between the United States and Australia. With the US thus blocked the Japanese could have easily invaded northern Australia.
Beyond any doubt conditions in the Pacific would have seriously deteriorated with the loss of Midway but the Pacific war always comes back to the fact that by 1942 Japan's industrial capacity had peaked, whereas the American war machine was still growing. By mid-1943, the U.S. was launching an Essex-class carrier at the rate of one ship every two months. By August 1945, 17 Essex-class flattops would enter service, to say nothing of 9 Independence-class light carriers and dozens of small escort carriers. Simply put the war's outcome hinged on US industrial capacity.
So losing at Midway would not have changed the end of the war but would have seriously affected the prosecution of the war. The loss of Midway would have placed great pressure on the Roosevelt administration to change the Allied "Germany First" strategy in favor of reclaiming the Pacific losses to protect Australia.
The U.S./Allied forces had to maintain the supply line to Australia, so, if the Japanese followed a triumph at Midway by seizing islands straddling that route, the Americans would have had to shift the Pacific war effort to liberating those islands first, which would have demanding the reallocation of troop transport and landing vessels from the European Theater to the Pacific making D-day impossible.
In fact in July 1942 Secretary of War Henry L. Stimson and the Joint Chiefs of Staff, frustrated by British resistance to undertaking an early cross-Channel attack, recommended a shift to the defensive in Europe and adoption of a Pacific First strategy. FDR vetoed this approach due mainly to the American victory at Midway, which seemed to indicate that the existing Allied forces in the Pacific could successfully take on Japan whereas a defeat at Midway would have argued the opposite requiring a reallocation of forces.
Abandonment of the "Germany First" strategy could have had no other effect but to prolong the war in Europe by many months, perhaps allowing the Soviet Union to gain control of Western Europe. Certainly hostilities would have ground on long enough for the Manhattan Project to complete the first atomic bombs, which the U.S. then would have dropped not on Japan but on targets in Germany. Victory at Midway would not have won Japan the war, but could well have given the Second World War a very different turn.
Consider that by June 1942, Oahu, was garrisoned by 100,000–150,000 soldiers. At the time of the Pearl Harbor attack the Japanese had estimated that they would need to deploy at least 45,000 men in the invasion of the Hawaiian Islands.
#1, that would be an invasion force 10 times larger than they had ever landed amphibiously at one time and
#2 was a serious underestimation of the manpower required for a successful invasion.
At the time of Midway the Japanese never seriously considered an invasion of the Hawaiian Islands
Returning to the loss of Midway, with the Japanese in control of the Island the August 1942 counteroffensive at Guadalcanal could not have occurred and the Japanese invasion of Australia and New Guinea could not have been stopped. In fact the entire South Pacific would have been open to Japanese invasion. The Japanese could have easily occupied the New Hebrides, Fiji, Samoa, and Tonga thus cutting the main line of supply between the United States and Australia. With the US thus blocked the Japanese could have easily invaded northern Australia.
Beyond any doubt conditions in the Pacific would have seriously deteriorated with the loss of Midway but the Pacific war always comes back to the fact that by 1942 Japan's industrial capacity had peaked, whereas the American war machine was still growing. By mid-1943, the U.S. was launching an Essex-class carrier at the rate of one ship every two months. By August 1945, 17 Essex-class flattops would enter service, to say nothing of 9 Independence-class light carriers and dozens of small escort carriers. Simply put the war's outcome hinged on US industrial capacity.
So losing at Midway would not have changed the end of the war but would have seriously affected the prosecution of the war. The loss of Midway would have placed great pressure on the Roosevelt administration to change the Allied "Germany First" strategy in favor of reclaiming the Pacific losses to protect Australia.
The U.S./Allied forces had to maintain the supply line to Australia, so, if the Japanese followed a triumph at Midway by seizing islands straddling that route, the Americans would have had to shift the Pacific war effort to liberating those islands first, which would have demanding the reallocation of troop transport and landing vessels from the European Theater to the Pacific making D-day impossible.
In fact in July 1942 Secretary of War Henry L. Stimson and the Joint Chiefs of Staff, frustrated by British resistance to undertaking an early cross-Channel attack, recommended a shift to the defensive in Europe and adoption of a Pacific First strategy. FDR vetoed this approach due mainly to the American victory at Midway, which seemed to indicate that the existing Allied forces in the Pacific could successfully take on Japan whereas a defeat at Midway would have argued the opposite requiring a reallocation of forces.
Abandonment of the "Germany First" strategy could have had no other effect but to prolong the war in Europe by many months, perhaps allowing the Soviet Union to gain control of Western Europe. Certainly hostilities would have ground on long enough for the Manhattan Project to complete the first atomic bombs, which the U.S. then would have dropped not on Japan but on targets in Germany. Victory at Midway would not have won Japan the war, but could well have given the Second World War a very different turn.