オレンジ計画
In Panama, during the 1920s, the Marine Corps conducted a few modest experiments concerning modern amphibious warfare. At the beginning of the 1930s American defense policy shifted as the threat of the expansionist Japanese Empire became more apparent. The establishment of the Fleet Marine Force and greater concentration on the feasibility of amphibious assault were the direct result. Developing the ability to capture Japanese held islands during a Pacific war against Japan was a vital part of US war contingency plans; War Plan Orange. It was not until these contingency plans described the necessity of amphibious capability that testing key maneuvers in amphibious landings was funded.