self-sustaining; long, drawn-out operations must be avoided to afford the greatest protection to the fleet; sea objectives must include a fleet anchorage. Undercover mission in the Central Pacific Ellis believed that US acquiescence to Japan's South Pacific Mandate, which allowed Japan to occupy islands that had previously been controlled by Germany, would enable Japan to operate behind a defensive screen to expand its territory and influence without being observed. Convinced that this course would eventually lead to war between Japan and the United States, Ellis determined to carry out intelligence gathering activities to obtain details on Japan's activities. On April 9, 1921, Ellis submitted a pro forma request to the commandant to conduct a clandestine reconnaissance mission to the Central Pacific to examine the Marshall and Caroline Islands. His request indicated that he expected to travel as a civilian and to provide an undated resignation that would enable the Marine Corps to deny knowledge of his actions if necessary. (In fact, the Marine Corps did not use the letter of resignation, and retained Ellis on its roll of active officers until he died. At the time of his death, Ellis was listed in payroll and personnel records as being on "extended leave," a status the commandant had directed his staff to use.) Shortly after he submitted his request he suffered another occurrence of neurasthenia; after recovering he asked to resume the intelligence mission in the Pacific. On May 4, 1921, Assistant Secretary of the Navy Theodore Roosevelt Jr. approved the request as the acting Secretary of the Navy. Ellis left the hospital the same day, and reported to Headquarters Marine Corps to finish making arrangements. To hide his identity as a military officer gathering intelligence abroad, Ellis turned to John A. Hughes, who was commissioned from the ranks with him in 1902. Hughes had been medically retired in 1920, after which he joined his father's import-export business, the Hughes Trading Company. Hughes provided Ellis with a cover identity as a traveling representative of the company. After a brief visit home to Kansas, Ellis traveled to San Francisco on May 28, 1921. He subsequently traveled to New Zealand and Australia via the American President Lines SS Maheno, and arrived on September 28. Ellis was soon hospitalized in Manila due to acute nephritis, an inflammation of the kidneys. After his discharge, he departed for Yokohama, Japan aboard SS President Jackson so he