Immigration and Border Control‪.‬

For the past two decades the United States, a country with a strong tradition of limited government, has been pursuing a widely popular initiative that requires one of the most ambitious expansions of government power in modern history: securing the nation's borders against illegal immigration. Congress and successive administrations--both Democratic and Republican--have increased the size of the Border Patrol from fewer than 3,000 agents to more than 21,000, built nearly 700 miles of fencing along the southern border with Mexico, and deployed pilotless drones, sensor cameras, and other expensive technologies aimed at preventing illegal crossings at the land borders. The government has overhauled the visa system to require interviews for all new visa applicants and instituted extensive background checks for many of those wishing to come to the United States to study, travel, visit family, or do business. It now requires secure documents--a passport or the equivalent--for all travel to and from the United States by citizens and noncitizens. And border officers take fingerprints and run other screening measures on all travelers coming to this country by air in order to identify criminals, terrorists, or others deemed to pose a threat to the United States. The goal is to create a border control system that ensures that only those legally permitted by the government to enter the territory of the United States will be able to do so, and that they will leave the country when required. The ambition of such an undertaking is little appreciated. For most of its history, the United States had only the loosest sort of border controls. Scrutiny of most visa applicants was cursory; few checks were done on incoming airline passengers; and it was possible to walk freely across almost any portion of the more than 7,500 miles of land borders with Mexico or Canada (Alden 2008).