structural:expansion, stylistic:style_transfer
Overview

In places where smuggling, migration, and infiltration are a problem, many countries fortify borders with fences and barriers, and institute formal border control procedures. These can extend inland, as in the United States where the U.S. Customs and Border Protection service has jurisdiction to operate up to 100 miles from any land or sea boundary. On the other hand, some borders are merely signposted. This is common in countries within the European Schengen Area and on rural sections of the Canada–United States border. Borders may even be completely unmarked, typically in remote or forested regions; such borders are often described as "porous". Migration within territorial borders, and outside of them, represented an old and established pattern of movement in African countries, in seeking work and food, and to maintain ties with kin who had moved across the previously porous borders of their homelands. When the colonial frontiers were drawn, Western countries attempted to obtain a monopoly on the recruitment of labor in many African countries, which altered the practical and institutional context in which the old migration patterns had been followed, and some might argue, are still followed today. The frontiers were particularly porous for the physical movement of migrants, and people living in borderlands easily maintained transnational cultural and social networks.