The Philippines, at that time an American protectorate, were also a Japanese target. The Japanese military concluded an invasion of the Philippines would provoke an American military response. Rather than seize and fortify the islands, and wait for the inevitable U.S. counterattack, Japan's military leaders instead decided on the preventive Pearl Harbor attack, which they assumed would negate the American forces needed for the liberation and reconquest of the islands. (Later that same day [December 8, local time], the Japanese indeed launched their invasion of the Philippines).