Mass shootings, like the horrific shooting at a Connecticut elementary school today, always make headlines. So do killings that involve high-profile people, like the 2011 attack on Arizona Congresswoman Gabrielle Giffords or the recent incident involving NFL player Jovan Belcher. Right up there are random acts of gun violence, like the man who killed two people in an Oregon mall this week before killing himself.
With each new tragedy, questions arise about whether victims would still be alive if the United States had stricter gun laws.
There are no easy answers. As arguments continue over how effective gun control laws are and could be, some experts say that criminals will find a way to access guns no matter what the rules are. Others are publishing studies showing that harsher restrictions can reduce certain kinds of violence and save lives.
On both sides of the debate, people tend to agree that guns are here to stay. Where there's still disagreement is the question of how best to keep firearms out of the hands of people who are most likely to abuse them.
"If we fixed all the gun laws and, presto, we fixed all the politics, would all the gun homicides go away immediately? Of course not, there are guns out there that people would use," said Daniel Webster, director of the Johns Hopkins Center for Gun Policy and Research in Baltimore. "But I tell you it would make a difference over the long haul in a substantial kind of way.
"We need to get beyond the pro-gun, anti-gun shouting match to get to what I think the heart of the matter is and something there's broad agreement on," he added. "Dangerous people shouldn't have guns."
Some states, including Arizona and Georgia, have lax laws that make it easy to buy cheap handguns directly from gun shops, while other states make firearms much harder to get. In New York, Massachusetts and Hawaii, for example, gun-buyers must visit a local law enforcement agency, where they are photographed, fingerprinted and given background checks before they can earn a license to buy guns.
In the few states with the most comprehensive regulations, Webster said, rates of gun-caused deaths are lowest. His research shows that big improvements could come from targeted regulations that focus on keeping guns away from people who probably shouldn't have them in the first place.
In one study, for instance, he and a colleague found that state policies that prohibited the sale of guns to people who were subject to restraining orders reduced the number of people killed in domestic-violence homicides by 19 percent.
Another study found an estimated 9 percent reduction in gun homicides following a Maryland law that banned a type of handguns, which are cheap, over-represented in crimes and prone to jamming and misfiring. That amounted to about 40 lives saved each year.
And in a California study, rates of violence went down after the implementation of a law that denied the purchase of firearms by people who had already committed violent misdemeanors.
Compared to other high-income countries, the United States' homicide rates are about seven times higher than average, Webster added, driven mostly by a firearm homicide rate that is 22 times higher than average. More than 31,000 people die in the U.S. from gunshot wounds each year.
"Is that simply because people in the United States are generally more violent?" he said. "I don't think so."
Not everyone agrees that stricter laws will make a difference. In interviews, criminals often say that one of their biggest fears is an armed citizen, said Frederick Bieber, a forensic expert at the Harvard Medical School in Boston. But, he argued, tight regulations often make it harder for ordinary people to get guns without hindering lawbreakers.
"I just don't know that more laws will prevent a mentally deranged person from stealing a gun or pushing someone off a subway platform," he said. "Many of the laws are so onerous that they prevent law-abiding citizens from having easy access to a constitutional right."
"I abhor violence and crime as much as anybody," he added. "But I have also been to too many crime scenes as a forensic DNA guy to wonder rhetorically, if that 80-year old woman had had a shotgun behind the door, might she not have been raped and tortured and murdered?"
Gun laws wouldn't prevent someone like the Oregon mall-shooter from stealing a weapon and going on a rampage, Bieber said. Instead, he believes that we need to spend more time studying the root causes of behavior in order to prevent violent acts.
The media's tendency to highlight mass shootings misses the point of the debate on gun laws, Webster added, pointing out that those kinds of random events account for a tiny fraction of overall gun violence.
More important, he said, is to figure out who the dangerous people are and to find a way to keep them from getting guns.
"If you let the water run in your basement and it's flooded, before you can get the water out and clean it all up, you have to turn the darn spigot off," he added. "We have to turn the spigot off that is allowing so many criminals to get guns relatively easy in many states."