With the closing of the east–west sector boundary in Berlin, the vast majority of East Germans could no longer travel or emigrate to West Germany. Berlin soon went from being the easiest place to make an unauthorized crossing between East and West Germany to being the most difficult. Many families were split, while East Berliners employed in the West were cut off from their jobs. West Berlin became an isolated exclave in a hostile land. West Berliners demonstrated against the Wall, led by their Mayor () Willy Brandt, who strongly criticized the United States for failing to respond. Allied intelligence agencies had hypothesized about a wall to stop the flood of refugees, but the main candidate for its location was around the perimeter of the city. In 1961, Secretary of State Dean Rusk proclaimed, "The Wall certainly ought not to be a permanent feature of the European landscape. I see no reason why the Soviet Union should think it is—it is to their advantage in any way to leave there that monument to communist failure."