Hart was appointed commander in chief, U.S.
Asiatic Fleet on July 25, 1939, and was promoted to
admiral the same day. He held that position at the commencement of hostilities in World War II between
Japan and the United States in December 1941. The majority of forces under Hart's command were located in the
Philippines, with a small force of destroyers and a light cruiser based in
Borneo. His command included the majority of the combat-ready US submarines in the
Pacific. Hart initially commanded U.S. naval forces from
Manila, but was forced to relocate to
Java on January 15, 1942, in light of rapid Japanese advances through the Philippine archipelago. On his relocation to Java, Hart was named Commander, Naval Forces,
ABDA Command, a joint British, Dutch, American and Australian military command, formed for purposes of holding the southern portions of the
Dutch East Indies against further Japanese advances. While in command of ABDA naval forces, ships under his command fought the
Battle of Balikpapan, a tactical victory, but strategic defeat for the allied forces. Hart held the command of the
U.S. Navy Asiatic Fleet until February 5, 1942, at which point the command ceased to exist as part of a broader U.S. military command restructuring in the
Southwest Pacific. Hart continued to hold the position of commander for ABDA naval forces until relieved of operational responsibilities on February 12, 1942. Hart formally was relieved of this title on February 16, 1942, when he left Java, ostensibly for health reasons (and for political reasons as he was undermined by his British and Dutch subordinate national component commanders). He returned to the US via Batavia to Ceylon on a British passenger vessel, and then onto the United States. President Roosevelt presented Hart with a Gold Star in lieu of a second
Distinguished Service Medal in July 1942 (his first Distinguished Service Medal having been awarded for his service in World War I) for "[h]is conduct of the operations of the Allied naval forces in the Southwest Pacific area during January and February 1942, was characterized by unfailing judgment and sound decision, coupled with marked moral courage, in the face of discouraging surroundings and complex associations." Hart was retired with the rank of
admiral in July 1942, but recalled to duty in August 1942 as a member of the U.S. Navy's
General Board. Hart retired from active duty a second time in February 1945, on his appointment to the U.S. Senate to fill the seat of Francis T. Maloney, on Maloney's death. ==Personal life==