On this day, American forces invade and take control of the Marshall Islands, long occupied by the Japanese and used by them as a base for military operations.
The Marshalls, east of the Caroline Islands in the western Pacific Ocean, had been in Japanese hands since World War I. Occupied by the Japanese in 1914, they were made part of the “Japanese Mandated Islands” as determined by the League of Nations. The Treaty of Versailles, which concluded the First World War, stipulated certain islands formerly controlled by Germany–including the Marshalls, the Carolines, and the Marianas (except Guam)–had to be ceded to the Japanese, though “overseen” by the League. But the Japanese withdrew from the League in 1933 and began transforming the Mandated Islands into military bases. Non-Japanese, including Christian missionaries, were kept from the islands as naval and air bases–meant to threaten shipping lanes between Australia and Hawaii–were constructed.
During the Second World War, these islands, as well as others in the vicinity, became targets of Allied attacks. The U.S. Central Pacific Campaign began with the Gilbert Islands, south of the Mandated Islands; U.S. forces conquered the Gilberts in November 1943. Next on the agenda was Operation Flintlock, a plan to capture the Marshall Islands.
Adm. Raymond Spruance led the 5th Fleet from Pearl Harbor on January 22, 1944, to the Marshalls, with the goal of getting 53,000 assault troops ashore two islets: Roi and Namur. Meanwhile, using the Gilberts as an air base, American planes bombed the Japanese administrative and communications center for the Marshalls, which was located on Kwajalein, an atoll that was part of the Marshall cluster of atolls, islets, and reefs.
By January 31, Kwajalein was devastated. Repeated carrier- and land-based air raids destroyed every Japanese airplane on the Marshalls. By February 3, U.S. infantry overran Roi and Namur atolls. The Marshalls were then effectively in American hands–with the loss of only 400 American lives.