Although negotiations restarted after the United States., . enforced an embargo against Japan they made little headway. Diplomats in Washington came close to agreements on a couple of occasions, but the United States was unwilling to accept any resolution that did not involve a Japanese withdrawal from China, and such a condition was unacceptable to Japan's military leaders. Faced with serious shortages as a result of the embargo, unable to retreat, and convinced that U.S.officials opposed further negotiations ,Japan's leaders came to the conclusion that they had to act swiftly. __ U.S. leaders had not given up on a negotiated settlement, and also doubted that Japan had the military strength to attack the U.S. territory .Therefore they were stunned when the unthinkable happened and Japanese planes bombed the U.S. fleet at Pearl Harbor on December 7, 1941. The following day , the United States declared war on Japan, and it soon entered into a military alliance with According to the excerpt why did the American leaders believe that US territories were safe from Japanese attack? They had negotiated an agreement for Japan's withdrawal from China. They believed the embargo had made Japan too weak to attack. They thought the distance between the United States and Japan was too great. They expected Japan to attack Germany next.