International rivers and national security: The Euphrates, Ganges–Brahmaputra, Indus, Tigris, and Yarmouk rivers1

To understand a state's incentives to invest in conflict or cooperation over their international rivers, this paper argues that it is necessary to appreciate the relationships a river can create and the national security threat riparians may confront. Rivers impose interdependent and vulnerable relationships, which can compromise a state's ability to respond effectively to floods and droughts, meet its domestic food and energy needs, dredge the river, maintain its drainage systems, and allocate its domestic water budget. The inability to accomplish these tasks can contribute to social, economic, and political losses that may threaten a state's territorial integrity. Regardless of whether a state is upstream or downstream, from these relationships it acquires leverage to manipulate the interdependence and vulnerability to inflict losses on its riparian neighbour. This argument challenges several assumptions within the existing literature, including the belief that a shortage of freshwater is the initial force producing a national security threat and that an upstream–downstream river bequeaths all advantages on the upstream state and leaves the downstream state purely dependent. As the paper shows, riparians confront a more complex relationship than captured by the existing literature.