The Philippines were central to Japan’s expectation

Would the United States have tried to reinforce the Philippines if Pearl Harbor had missed the main fleet?

Probably, because political pressure favored reinforcement, which closely matched the Japanese hoped-for operational sequence.

The discussion argues that political pressure could drive the United States to attempt reinforcement even when senior commanders doubted the Philippines could be saved. Japanese planners wanted the Americans to move toward their own threatened base, much as the Russian fleet at Tsushima had been trying to reach a friendly destination rather than attack Japan itself. Submarines, torpedo craft, destroyers, and cruisers would attrit that advance before the Japanese battle line engaged northeast of the Philippines. This was not a trick designed to lure the enemy toward Japan for no reason; it exploited an objective Washington already had reason to defend. The Philippines therefore linked War Plan Orange to the geography on which Kantai Kessen expected to operate.