They Shall Not Cross

This monograph discusses the inadequacy of current U.S. Army doctrine for incorporating water barriers into a defensive scheme, and makes recommendations regarding improving that doctrine. The monograph first examines the current status of doctrine for the incorporation of river barriers into defensive plans and finds adequate doctrine lacking. The paper then provides the necessary foundation for the creation of a new doctrine through an examination of: existing 'theories' for the defense of river barriers; the methods of defense used in World War Two (especially against the Soviets) and their degree of success; and the most significant changes apparent since World War Two in offensive river-crossing doctrine and capabilities (especially Soviet) and their likely impact on defensive theory and lessons from previous practice. The monograph concludes that defense on the far shore seems to hold most promise for success in modern war, but also that further study needs to be completed in many areas before a fully adequate doctrine could be written. It then recommends specific actions to assist in the creation of such a doctrine.