In 1940, Bloch became commander of the 14th Naval District, Pearl Harbor, normally an enjoyable preretirement assignment. As a warning gesture to Japan in 1940, however, President Franklin D. Roosevelt transferred the West Coast Fleet, Bloch's former command, from California to Hawaii. Bloch sought to strength Hawaiian defenses, but he encountered much interference and obstruction from the fleet's new commander, Admiral Husband Edward Kimmel. Yet Bloch's own opposition to the installation of antitorpedo nets contributed to the disastrous Japanese attack on Pearl Harbor of 7 December 1941. Although both Kimmel and General Walter Short, the army commander, were removed from their commands, Bloch served out his term until April 1942, when he retired. A congressional inquiry subsequently exonerated him from all responsibility for the Pearl Harbor debacle.
Recalled to Washington in April 1942 to serve on the navy's General Board, he retired in August 1942 at the rank of full admiral. In retirement, he headed the Navy Board for Production Awards until the end of World War II. Bloch died in Washington, D.C., on 6 October 1967.
Clausen, Henry C., and Bruce Lee. Pearl Harbor: Final Judgment. New York: Crown Publishers, 1992.; Conroy, Hilary, and Harry Wray, eds. Pearl Harbor Reexamined: Prologue to the Pacific War. Honolulu: University of Hawaii Press, 1990.; Prange, Gordon William, with Donald M. Goldstein and Katherine V. Dillon. Pearl Harbor: The Verdict of History. New York: McGraw-Hill, 1986.