The Cactus Air Force

On August 29, 1942, Rear Admiral John S. McCain, Sr. messaged Pacific Fleet Commander Admiral Chester W. Nimitz- "Cactus can be a sinkhole for enemy air power and can be consolidated, expanded, and exploited to (the) enemy's moral hurt. The reverse is true if we lose Cactus." In these two sentences, he described the crucial importance of the Guadalcanal campaign.
Upon receiving orders to attack Pearl Harbor in November 1941, Japanese fleet commander Admiral Isoroku Yamamoto had replied, "In the first six to twelve months of a war with the United States and Great Britain I will run wild and win victory upon victory. But then, if the war continues after that, I have no expectation of success." He was off by four days, with Kido Butai's offensive power destroyed at Midway on June 4, 1942, four days short of six months from the Pearl Harbor attack.
However, the Japanese were still strong, and were determined to force the United States to recognize their expansion by defeating our forces in battle before the inherent industrial superiority of the United States could be brought to bear on the outcome. Thus, the battle of Guadalcanal, the first offensive operation undertaken by the United States and her allies in the Pacific War, was a testing ground of which side would prevail. "Cactus," the code name for the island, did indeed become a sinkhole for enemy air and naval power, forces whose losses could never be made good by replacements of equal quality. The week following the Pacific War's first anniversary, Yamamoto informed the Japanese high command that the surviving troops on Guadalcanal must be evacuated if possible. After that he could only hope to delay the Allied reconquest of the Solomons and expulsion of Japanese forces from the South Pacific.
The air battles during the three months between August 20, 1942, when the first Marine air unit arrived on the island, and November 15, when the last attempt by the enemy to send reinforcements to retake the island was defeated, were perhaps the most important three months of the Pacific War. After November 15, 1942, the United States never looked back as its forces moved across the Pacific to the war's inevitable conclusion, growing stronger every month as the enemy grew weaker.