“Discretion, (Daniel Webster) argued, allows police to wade into that middle ground even when the law might not explicitly ban a person from owning a gun. One example: Perhaps a person’s wife recently told a police officer that someone has suicidal or homicidal thoughts. If that person then comes in and tries to get a license, the police chief could use that discretion to deny the application, even if expressing violent thoughts is not explicitly disqualifying under the law.

“To this point, there are multiple issues within gun violence. An assault weapons ban likely won’t have an effect on suicides, gang shootings, or domestic violence, for example, but it may have a significant effect on mass shooting deaths. Other policies may have different effects in different categories.

“Wherever researchers ultimately land on the effect of individual laws versus the whole picture, there’s little debate that Massachusetts has a fairly robust, effective set of gun laws. That includes not just the licensing system, but also a safe storage law, the registration portal, legal requirements for reporting lost or stolen guns, restrictions on private sellers, bans on assault weapons and large-capacity ammunition magazines, a list of prohibited gun buyers that extends far beyond federal law, oversight on gun dealers that goes above the federal standard, and much more.” – German Lopez in Vox, I Looked for a State That’s Taking Gun Violence Seriously. I Found Massachusetts.