The United States is looking at building fences along the border with Canada to help keep out terrorists and other criminals. The U.S. Customs and Border Protection agency has proposed the use of "fencing and other barriers" on the 49th parallel to manage "trouble spots where passage of cross-border violators is difficult to control." The border service is also pondering options including a beefed-up technological presence through increased use of radar, sensors, cameras, drones and vehicle scanners. In addition, it might continue to improve or expand customs facilities at ports of entry. The agency considered but ruled out the possibility...