It is difficult for non-Americans to understand the United States' relationship with guns. Even those who know about the Second Amendment are perplexed by the insistence of gun rights supporters that a clause with several caveats written over two centuries ago in a particular political environment could be seen today as a blanket endorsement of gun ownership with no limitations. More puzzling still is the gap between public opinion — which shows majority support for some restrictions on the ability to purchase a gun — and a political system that has proven unable to take any action to that end.

That inaction is even more incomprehensible given the scale of the tragedy created by the easy availability of guns. It is estimated that there are 40 million more guns than citizens of the U.S., or more than 350 million guns. More than 100,000 people have been killed as a result of gun violence over the past decade in America, and millions more have been the victim of assaults, robberies and other crimes involving a gun. During that same period, hundreds of thousands of other people committed suicide with a gun and nearly half a million people suffered other gun injuries. Gun control advocates note that guns in the home are 22 times more likely to be involved in accidental shootings, homicides or suicide attempts than acts of self-defense.

The alarming growth in the number of mass shootings has focused attention on the need for action. Depending on the criteria used, there were either four or six such incidents in the U.S. in 2015. While any attack of this type is tragic, the most horrific incident was the shooting at Sandy Hook elementary school in 2012 which claimed the lives of 26 people, 20 of them children. The shooting of 14 people by two Islamic State supporters in San Bernadino, California, last month forced U.S. President Barack Obama to take action.