Which structure currently operates as a "virtual fence:"  Boarder Wall or Mexico-United States Barrier?
Mexico–United States barrier The Mexico–United States barrier is a series of walls and fences along the Mexico–United States border aimed at preventing illegal crossings from Mexico into the United States. The barrier is not one continuous structure, but a grouping of relatively short physical walls, secured in between with a "virtual fence" which includes a system of sensors and cameras monitored by the United States Border Patrol. As of January 2009, U.S. Customs and Border Protection reported that it had more than 580 mi of barriers in place. The total length of the continental border is 1,989 mi .
Roosevelt Reservation The Roosevelt Reservation is a 60 ft strip of land on the United States side of the United States-Mexico Border under the jurisdiction of the United States Federal Government. It was established in a 1907 Presidential Proclamation (35 Stat. 2136) by Theodore Roosevelt in order to keep the land "free from obstruction as a protection against the smuggling of goods between the United States and Mexico".