A Pacific war without a European war

How would the Pacific War change if Europe did not enter a general war?

Japan would face both the full Royal Navy and US Navy because Britain and America each needed influence over the postwar Far East.

If Germany and Italy remained out of war, Britain could direct far more of the Royal Navy toward the Pacific. The United States would still enter the struggle with its own expanding fleet. Neither power could allow the other to defeat Japan alone because the victor would dominate the postwar Far East. Japan would face an Anglo-American coalition, probably joined by Dutch, French, and possibly Italian forces.