The formulation of the AirLand Battle doctrine in the late 1970s and early 1980s laid bare the difficulty of coordinating efforts among various service branches. AirLand Battle attempted to synthesize all of the capabilities of the service arms of the military into a single doctrine. The system envisioned ground, naval, air, and space based systems acting in concert to attack and defeat an opponent in depth. The structure of the armed forces effectively blocked realization of this ideal. The U.S. invasion of Grenada in 1983 further exposed the problems with the military command structure. Although the United States forces easily prevailed, its leaders expressed major concerns over both the inability of the different service branches to coordinate and communicate with each other, and the consequences of a lack of coordination if faced with a more threatening foe.