After the signing of the Treaty of Guadalupe Hidalgo, the process to mark the conceptual and physical border began. Cartographers created  this line on paper. Surveyors crudely walked the 2,000 mile boundary and marked the divide with stone markers. In the nineteenth century local militias and police forces were empowered to enforce these demarcations. Long before any formal fences were constructed, local troops and police manned the border. The militarization of the border in this way took the place of any physical infrastructure. Indeed, formal fencing along the border was haphazard, consisting of cattle fencing and walls constructed by local governments and, later, barbed wired recycled from the Japanese Internment camps of the 1940’s. In 2006, Congress passed the Secure Fence Act, calling for the creation of 700 miles of fortified fencing. However, what this clearly illustrates, is that the border was not and is not a physical barrier; it is porous rather than solid.