Why Do Countries Build Walls?

<p>Why do countries build fences and walls at their border and under what conditions are those walls and fences likely to work as intended? These questions are obviously topical right now, with the US-Mexico border a hot button issue in the US presidential election; and the Syrian refugee crisis dominating discussion the Europe  </p> But fences and their effectiveness have largely remained off the radar of any rigorous academic study. Until now. In the most recent edition of the journal International Security, political scientists Ron Hassner and Jason Wittenberg of UC Berkeley compiled what is the first-ever dataset of w...