United States-Mexican border zone

The regulation of people and products moving between the United States and Mexico, most visible along their 2,000 mile-long boundary, also depends on the complementary function of a series of border zones. Located adjacent to the boundary, they form part of each country's administrative attempts to balance national interests and the particular needs of the border area. The boundary, limit of national sovereignty, allows a certain degree of interaction; border zones, while broadening the area of contact, impose some limitations upon it. The form and function of border zones have varied over time, just as administration of the boundary has adjusted to change. Since residents of Northern new Spain met participants of American westward expansion, the two central governments have used border zones to impose restrictions on the interchange. Mexico has feared its northern neighbor's territorial ambitions and economic power. Immigration and drugs from Mexico concern the United States