“Maritime security.” The phrase, and the nebulous set of missions that loosely fall underneath it, came into expanded use in the decades after September 11, including in U.S. strategic documents. Even during the height of interest in maritime security, however—say, around 2007 and the publication of A Cooperative Strategy for 21st Century Seapower—it was not clear how those missions could or should be prioritized with respect to other strategic challenges. As the Department of Defense, and the Navy with it, reorients to great power competition, it will only become easier for those questions to slide into the background. And yet, as we will see below, historical trends and emerging patterns will conspire to keep the littorals at the forefront of policymaker’s minds. Alongside the renewed focus on traditional adversaries, therefore, operations in green and brown waters driven by unconventional threats will likely play an enduring role in U.S. foreign policy.
In his book Out of the Mountains, counterinsurgency strategist David Kilcullen sets out a compelling argument for taking the littorals seriously. Kilcullen’s argument is focused on events ashore, but his articulation of the global drivers shaping the littorals can be made equally valuable for the seaward end of the domain. The premise underlying these drivers is based on one simple principle: conflict happens where people are.1 So, where are the people?
In response, Kilcullen identifies four “megatrends” of demography and economic geography that suggest where we will find most of the world’s population in the coming decades. “Rapid population growth, accelerating urbanization, littoralization (the tendency for things to cluster on the coastlines), and increasing connectedness” all suggest that populations are concentrating in networked, urban, dense, littoral communities.