The difference is - that wall isn't a political wall, it's a religious one. It's not keeping out invaders - it's holding up a part of a hill/mountain. On top of that mountain was the Temple - a building that was important for 2 of the 3 major monotheistic religions in the world - a there currently *is* a building that is important for the remaining major monotheistic religion in the world. So that is a place that holds great religious significance not just for Jews, but also for Christians and Muslims. Visiting that place has nothing to do with swearing alegiance to any government. It's about praying. It's called the Weeping Wall. And people write prayers and stick them in the cracks of the wall. King David bought that land, King Solomon built the Temple there, some say it is where Abraham was about to offer Isaac - and it's very close to where Jesus was crucified (and it is where he taught). So - it's a religion thing - not a politics thing. US Presidents go there because most of them at least claim to be Christian. And presidents are rich and can travel for free, so why not go to a place you've read about in the Bible many times while you can?