Traditionally, debates over how to reduce gun violence have focused on the gun control controversy: Anti-gun groups have pushed for restrictions or bans on guns, while pro-gun groups have argued that criminals who use guns, not guns themselves, should be locked up. More recently, efforts to reduce gun violence have focused on new technologies that could make guns safer. One proposed approach to making guns safer is to install trigger locks, which would require the user to know the proper combination to fire the gun. A more advanced, so-called “smart gun” technology would recognize a user’s thumbprint, so that only the owner of a gun could fire it.

Proponents of trigger locks and smart guns say that they are the equivalent of putting safety caps on bottles of poison. Gun makers have also supported the new technologies...