Those who have only a casual knowledge of the Second World War might know little more about the Battle of Midway than the fact that it was an important American victory in the Pacific Theater. After all, the war had countless major battles, and a great many of them involved far more men and arms than fought at Midway. A tally of the forces engaged and lost there, pales to insignificance in the face of the much larger battles later in the war, particularly in Europe. But in fact, the Battle of Midway was one of the most important battles of the war, in any theater. Indeed, some would argue that it was the most important of them all. For had the American side lost at Midway (which any reasonable analysis prior to the battle would readily support), not only would all of the subsequent allied successes in the Pacific theater been severely delayed or obviated altogether, but virtually all of world history from that point forward would certainly have been altered almost beyond comprehension.
In brief, here's what happened at Midway, as related on the U.S. Naval History and Heritage Command web site:
The Battle of Midway, fought over and near the tiny U.S. mid-Pacific base at Midway atoll, represents the strategic high water mark of Japan's Pacific Ocean war. Prior to this action, Japan possessed general naval superiority over the United States and could usually choose where and when to attack. After Midway, the two opposing fleets were essentially equals, and the United States soon took the offensive. Japanese Combined Fleet commander Admiral Isoroku Yamamoto moved on Midway in an effort to draw out and destroy the U.S. Pacific Fleet's aircraft carrier striking forces, which had embarrassed the Japanese Navy in the mid-April Doolittle Raid on Japan's home islands and at the Battle of Coral Sea in early May.
He planned to quickly knock down Midway's defenses, follow up with an invasion of the atoll's two small islands, and establish a Japanese air base there. He expected the U.S. carriers to come out and fight, but to arrive too late to save Midway and in insufficient strength to avoid defeat by his own well-tested carrier air power. Yamamoto's intended surprise was thwarted by superior American communications intelligence, which deduced his scheme well before battle was joined. This allowed Admiral Chester W. Nimitz, the U.S. Pacific Fleet commander, to establish an ambush by having his carriers ready and waiting for the Japanese. On June 4, 1942, in the second of the Pacific War's great carrier battles, the trap was sprung. The perseverance, sacrifice and skill of U.S. Navy aviators, plus a great deal of good luck on the American side, cost Japan four irreplaceable fleet carriers, while only one of the three U.S. carriers present was lost. The base at Midway, though damaged by Japanese air attack, remained operational and later became a vital component in the American trans-Pacific offensive. Winston Churchill said of the Battle of Midway, "this memorable American victory was of cardinal importance, not only to the United States but to the whole Allied cause...At one stroke, the dominant position of Japan in the Pacific was reversed." And that is why Midway was among the most important battles of the war, for if the Japanese had prevailed and the order of battle certainly suggests that they should have considered what would have ensued.
All of the following are highly likely: 1.) There would have been no invasion of Guadalcanal in 1942. 2.) Because of that, a Japanese threat to Australia, blunted at Coral Sea, would have been renewed, with isolation likely and perhaps even partial occupation. 3.) A threat of that magnitude to the Australian homeland may have resulted in the recall of their army from North Africa, where Rommel's Afrika Corps was still a threat to the Suez Canal. 4.) With Australia neutralized, MacArthur would have had no convenient springboard for his return the Philippines, and he may have even risked the capture that he avoided at Corregidor. 5.) Without Australia, American submarines would have been denied the advance bases that allowed them to prey so successfully upon Japanese shipping in the western Pacific. 6.) With the Japanese in control of Midway, the threat to Hawaii would have been enormous. Their long range plans included a full scale invasion in 1943, the success of which would likely have led to carrier raids against the U.S. Pacific coast. 7.) With a powerful enemy virtually on its western shores, American resolve to prosecute the war in Europe would have been severely tested. And a reduced American commitment in Europe would have led to one of two probable scenarios, both of which are painful to contemplate: (a) An allied invasion of France in June 1944 would not have been possible, at least not then, giving the Nazis additional time to fortify their western defenses and thus make a successful invasion less likely. A delayed or even failed invasion in the west could have improved the Germans' ability to defend themselves in the east, allowing Hitler and the Nazis to remain in power far longer than they did, with unimaginable consequences for Europe. (b) Or, alternately, the lack of American-British pressure in the west would have allowed the steamrolling Red Army to overrun all of Germany, not just the eastern third. Communist dominance of the entire European continent could easily have resulted, bringing a far more dismal set of conditions at the start of the Cold War than what actually occurred. But none of those things came to be, because of the Incredible Victory, the Miracle at Midway. It shouldn't have happened but it did nonetheless, through amazing courage, divine intervention, or unbelievable luck, or a combination of all three.