USS Greer (DD–145) was a in the United States Navy, the first ship named for Rear Admiral James A. Greer (1833–1904). In what became known as the "Greer incident," she became the first US Navy ship to fire on a German ship, three months before the United States officially entered World War II. The incident led President Franklin D. Roosevelt to issue what became known as his "shoot-on-sight" order. Roosevelt publicly confirmed the "shoot on sight" order on 11 September 1941, effectively declaring naval war against Germany and Italy in the Battle of the Atlantic. Greer was launched by William Cramp & Sons Ship & Engine Building Co., Philadelphia, 1 August 1918; sponsored by Miss Evelina Porter Gleaves, daughter of Rear Admiral Albert Gleaves; and commissioned 31 December 1918, Commander C. E. Smith in command. Service history 1919 to 1941 Greers shake down took her to Azores, from which she rendezvoused with , carrying President Woodrow Wilson home from the Versailles Peace Conference, and escorted her to the United States. After exercises in coastal waters, Greer was assigned to Trepassey Bay, Newfoundland, for duties during a transatlantic flight by four Navy seaplanes, one of which, NC-4, safely completed the historic undertaking. After further training exercises and a European cruise, Greer was assigned to the Pacific Fleet, reaching San Francisco 18 November 1919. Six months' duty with the Pacific Fleet terminated 25 March 1920, when Greer sailed to join the Asiatic Fleet. After standing by off Shanghai to protect American lives and property during riots there in May, Greer sailed to Port Arthur and Dairen on intelligence missions and returned to Cavite, Philippines, for fleet exercises. The destroyer returned to San Francisco 29 September 1921 via Guam, Midway, and Pearl Harbor. Greer decommissioned at San Diego 22 June 1922, and was placed in reserve. Greer recommissioned 31 March 1930, Commander J. W. Bunkley in command. Operating with the Battle Fleet, she participated in a variety of exercises along the coast from Alaska to Panama, with an occasional voyage to Hawaii. Transferred to the Scouting Fleet 1 February 1931, she cruised off Panama, Haiti, and Cuba before being attached to the Rotating Reserve from August 1933 to February 1934. Training exercises, battle practice, and plane guard duty filled Greers peacetime routine for the next 2 years. She sailed for the East Coast and duty with the Training Squadron 3 June 1936. After