Can mandatory liability insurance for gun owners reduce violence? These local governments think so.

The idea has been floated for years, and it may seem straightforward enough: if gun owners were required to purchase liability insurance, proponents argue, they would have to follow safe practices to limit their financial and legal risk, thus reducing incidents of gun violence. 

But as New Jersey and the city of San Jose, California, have found, actually implementing the idea can be quite difficult. 

A recently enacted gun control law in New Jersey that among other things required gun carriers to purchase mandatory liability insurance was scheduled to go into effect on July 1, until it was blocked by U.S. District Judge Renée Marie Bumb.