In the aftermath of the Orlando shooting — the deadliest in recent U.S. history, with 49 victims — calls for gun control have once again grown louder. In fact, they were shouted on the House floor on Monday. After Speaker Paul Ryan led a moment of silence, Democrats yelled, "Where's the bill?" at him, asking for new gun control measures.
This isn't new. The word "doomed" has become a common adjective to describe gun control efforts. Mass shootings like those in San Bernardino, Calif.; Sandy Hook Elementary School in Newtown, Conn.; and Fort Hood, in Texas, looked like they might fuel efforts to tighten laws, but gun control advocates have found their efforts perpetually frustrated.
Efforts to pass federal gun control measures often get a lot of press, but state and local laws also play a big part in determining how people can purchase and own guns. After the Colorado Planned Parenthood shooting last year, President Obama asked Congress, as well as state and local governments, to take action.
The strictness of gun laws varies widely from state to state. We've put together state-by-state maps on some of the most important gun laws. Check out what nine types of gun-safety measures look like in your state, via data from the Law Center to Prevent Gun Violence:
The question of state laws' effectiveness regularly becomes a central point of debate after mass shootings. Florida's laws are the 28th strongest in the nation, according to the Law Center to Prevent Gun Violence; on its gun law scorecard, it gives Florida an F. Hillary Clinton called out Florida's gun laws in a Monday speech responding to the shooting.
California has the toughest gun laws in the nation, according to the Law Center, getting an A-minus. (You might notice that California is colored in on all of these maps.) And, of course, as the AP pointed out after San Bernardino, those tough gun laws "failed to stop [a] mass shooting."
That is one point that gun rights advocates point to after mass shootings as evidence that stricter gun laws aren't necessary — because they're ineffective. Many of the proposed gun control policies from President Obama and presidential candidates since San Bernardino wouldn't have stopped this particular attack, as the Washington Post's Philip Bump writes.
But gun control advocates point beyond isolated incidents to broader trends, like data showing that tougher state gun laws are correlated with fewer gun deaths (a statistic that includes not only homicides and accidents but also America's many gun suicides).
And to the degree that stricter gun laws keep gun ownership levels down, it could mean less violent crime. Several studies have shown a link between firearm ownership rates and the risk of being a homicide victim. In a 2015 study, for example, researchers at Harvard University found that higher levels of firearm ownership were associated with higher levels of firearm assault, firearm robbery and firearm homicide — when controlling for demographic factors like age and race.
That study, and many others like it, show a link between gun ownership and crime or deaths, and, therefore, support the hypothesis that more guns mean more gun-related crime and death, though they do not establish causality.
Though efforts to pass more gun control legislation have stalled at the federal level in the past few years, some Americans will vote on it at the state level next year. In November, measures requiring universal background checks (that is, checks for private and gun-show purchases) will be on the ballot in Nevada, and gun control advocates are hoping to vote on it in Maine as well.
Editor's note: This post was originally written in December 2015 and was updated on June 14, 2016, to reflect the Orlando shooting as well as new data from the Law Center to Prevent Gun Violence.