Japan hoped to defeat the US Pacific Fleet and use Midway as a base to attack Pearl Harbor, securing dominance in the region and then forcing a negotiated peace.

Why did America want Midway?

The United States was inspired to invest in the improvement of Midway in the mid-1930's with the rise of imperial Japan. In 1938 the Army Corps of Engineers dredged the lagoon during this period and, in 1938, Midway was declared second to Pearl Harbor in terms of naval base development in the Pacific.

Why was Midway so important?

The Battle of Midway became one of the most important American naval victories of World War II. ... Code-breakers were able to decipher Japanese naval code, allowing American leaders to anticipate Japanese maneuvers. The U.S. Navy was then able to launch a surprise attack on the larger Japanese fleet in the area.