In a pair of recent decisions, the Supreme Court has made it clear that Americans have a constitutional right to own handguns for self-defense. But the court will nonetheless allow "reasonable regulations" on firearms.
The country appears set, following the mass shootings at a school in Newtown, Conn., to have a debate about what restrictions should be put in place.
Members of Congress have already signaled their intent to introduce gun-control legislation next year, which President Obama has indicated in recent days will be a priority.
"If there's anything that's going to move the legislative agenda, this has to be it," says Harry L. Wilson, director of the Institute for Policy and Opinion Research at Roanoke College. "If Newtown does not produce meaningful legislation, what will?"
Still, Wilson cautions that many of the gun restrictions likely to be debated could have limited efficacy in preventing mass shootings. In terms of the political debate, he notes, supporters of gun owners' rights have won nearly every legislative battle in recent years.
But it's possible that Newtown will be a turning point. If that's the case, the argument over gun control is likely to tackle three major questions, according to Jon Lowy, director of the Brady Center to Prevent Gun Violence's Legal Action Center.
"The basic breakdown for most of it is, who should be allowed to buy guns, how should they be allowed to buy them and what should they be allowed to buy?"
The federal government banned certain types of semiautomatic weapons from 1994 to 2004, along with high capacity ammunition magazines. The law specified 19 particular models that were made illegal.
To keep manufacturers from issuing similar weapons under new names, the law defined an assault weapon as one that could accept a detachable magazine and also had any two characteristics from a list of features that included such things as a pistol grip and a folding or telescoping stock.
Sen. Dianne Feinstein, a California Democrat and sponsor of the original ban, said on NBC's Meet the Press on Sunday that she will introduce legislation next year to take "weapons of war off the streets of our cities."
"It will ban the sale, the transfer, the importation and the possession, not retroactively but prospectively," Feinstein said. "And it will ban the same for big clips, drums or strips of more than 10 bullets."
There's a ban on assault weapons currently in place in Connecticut that mirrors the old federal law in declaring a gun illegal if it has a detachable magazine and any one feature from the old federal list rather than two.
Lowy points out that, like the old federal ban, this is a less strict definition of regulated weapons than the state ban in place in California, which he suggests Feinstein could use as a model.
But a renewed ban that does not remove from circulation existing weapons would have limited effect, says Wilson, author of Guns, Gun Control and Elections.
There are already plenty of weapons out there — and likely to be more in the coming days and weeks, as gun owners rush to stock up either for personal protection or to invest in weapons that would become more valuable following a ban.
"The assault-weapon ban will be reintroduced, but I'm not sure it can pass the Senate," Wilson says. "It certainly won't pass the House."
Jared Loughner, who shot Democratic Rep. Gabrielle Giffords and killed six of her Arizona constituents early last year, fired 31 bullets from a 33-round extended magazine before bystanders were able to subdue him while he attempted to reload.
High capacity magazines are used "in virtually all of these mass shootings that you see," Lowy says. "High capacity magazines are what enable you to engage in this prolonged assault."
Connecticut bans assault weapons, but does not ban high capacity magazines. Congress may debate the merits of placing some kind of limitation on the number of rounds a shooter can fire before having to stop and reload.
"I don't know anyone in the sporting or hunting arena that goes out with an assault rifle," West Virginia Democratic Sen. Joe Manchin, considered a supporter of gun owners' rights, said on MSNBC's Morning Joe on Monday. "I don't know anyone that needs 30 rounds in a clip to go hunting. I mean, these are things that need to be talked about."
Still, it takes hardly any time at all for a competent shooter to stop and reload.
For nearly 20 years, federal law has required background checks on gun purchasers, to make sure they are eligible. There are many individuals barred from owning firearms, including felons, those who have been dishonorably discharged from the armed services and those adjudicated as "mentally defective."
How to keep guns out of the hands of the mentally ill is bound to be part of any gun-control discussion. Numerous states have restrictions in this area that are tighter than federal law.
Calling on states to do a better job of uploading their mental health records into national databases would address this issue without in any way impinging on gun rights, says Wilson, the Roanoke College public affairs professor.
"The only real legislation that came out of Virginia Tech was a mandate for mental health records for the national criminal background mental health checks," he says. "Many states have done almost nothing."
Last year, the House passed a bill that would block the Department of Veterans Affairs from determining that a veteran is mentally incompetent for purposes of gun control, unless that person was found to be a danger to himself or others by a judge.
Federal law requires licensed gun dealers to conduct background checks on their customers. But private transactions between persons "not engaged in the business" are not covered, making it easy to avoid background checks in sales conducted between private parties in person or over the Internet.
Under the terms of a 1986 law, even licensed firearms dealers can sell guns without background checks away from their principal place of business, according to the Congressional Research Service.
"Forty percent of sales are done without background checks," says Lowy, of the Brady Center. "This is the top of the list of policies that should be considered."
According to polling conducted this summer for Mayors Against Illegal Guns, 74 percent of members of the National Rifle Association and 87 percent of non-NRA gun owners support making background checks universal for all gun purchases.
Attempts to close the so-called gun show loophole have been attempted in Congress repeatedly in recent years, without success. "That's going to come up," says Wilson, the Roanoke professor. "But if you look at mass shootings, they get their guns legally, or they steal them from someone who got them legally."
The trend in recent years in both Congress and the states has been to expand gun owners' rights, rather than to restrict them. After the Virginia Tech shootings in 2007, for instance, numerous states extended the right to carry concealed weapons onto college campuses.
The 7th Circuit Court of Appeals last week threw out a ban on concealed weapons in Illinois, which was the last state with such a law still in place.
On the day before the Newtown shootings, the Michigan Legislature passed legislation to allow citizens to carry concealed weapons in more places, including schools. The Ohio Legislature also passed a bill last week that would allow people to carry concealed weapons in more places.
Last year, the House passed a bill that would require states to honor concealed-carry permits issued in other states in many cases. Congress in recent years has enacted provisions that allow people to carry firearms in national parks and on Amtrak trains.
Given reports that Adam Lanza, the Newtown shooter, turned his gun on himself when he heard the approach of law enforcement, some may argue that it should be easier to carry weapons for purposes of self-defense, Wilson says.
Copyright 2016 NPR. To see more, visit http://www.npr.org/.