President Fillmore had forbidden Perry to use threats or force. As a lawyer, Fillmore believed that the Shogunate would respond reasonably to American concerns about U.S. mariners washed up on Japanese shores and the need to repatriate Japanese fishermen washed up on American shores.
Fillmore's instruction to Perry was to avoid using aggressive methods. As a lawyer, Fillmore assumed that the Shogunate would respond sensibly to American concerns about U.S. sailors stranded in Japan and the need to return Japanese fishermen who had been rescued by Americans.