Just last week I was in Israel and visited the West Bank city of Bethlehem, where a young Palestinian man, Noor, took me around. As we turned a corner in the city, all of a sudden I confronted the wall that separates the West Bank and Israel. Up close, it is huge, imposing, cold and haunting. Here in the U.S., the federal government shutdown enters week three, locked in a showdown over a wall between the U.S. and Mexico. I wonder, what is the meaning of such walls?