here’s nearly one gun in the U.S. for every American, a figure that makes the country by far the most heavily armed nation in the world. (No. 2 is Yemen, an impoverished Middle Eastern country perpetually on the brink of civil war.) U.S. gun laws are relatively relaxed, and perhaps not incidentally, America has the highest homicide rate by gun among developed nations. In the wake of mass killings, other countries have adopted a range of new gun restrictions.