All Border Walls Have Something in Common

I spent most of the last two days driving and walking along the border fence at Brownsville, Texas. It's not the first barrier of this kind that I've seen. They're going up everywhere -- in more than 40 countries now: Donald Trump's calls for a powerful border wall are part of a trend. Though their reasons for existence, styles and histories vary, they are also similar in several important ways.

The first similarity is the free human being's natural emotional reaction to living close to a fence that usually breaks a vibrant cross-border community in two. In 1973, German psychologist Dietfried Mueller-Hegemann published a book describing the symptoms of something he called the Wall Disease. East Germans living next to the Berlin Wall suffered from depression, alcoholism and other signs of hating their life more than their luckier compatriots who lived further away from the wall. In other areas neighboring walls the symptoms are different, but the psychological pressure is equally harsh.