WASHINGTON - Mass shootings have provided the greatest catalyst for gun-control legislation out of Congress in the last 25 years, an analysis of gun laws shows, but the bills don't always become law.
Calls for more gun laws were sparked Friday after the shooting at Sandy Hook Elementary School in Newtown, Conn., in which 26 people were killed. Another victim was killed at another location, and the suspected killer committed suicide at the school.
Sen. Dianne Feinstein, D-Calif., said her office has been working on a new version of the assault weapons ban for a year and planned to introduce it the first day of the new Congress in January.
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Feinstein was one of the original authors of the first assault weapons ban that expired in 2004.
"It will ban the sale, the transfer, the importation and the possession. Not retroactively but prospectively. And it will ban the same for big clips, drums or strips of more than 10 bullets," she said on NBC'sMeet the Press. "So there will be a bill."
While members of Congress have called for bills that would make background checks more efficient, renew the assault weapons ban and other measures, these bills rarely make it through both chambers of Congress.
Congress last passed a law tightening restrictions on gun ownership in 2007 following the mass shooting at Virginia Tech in which 32 people were killed and 17 injured. A 23-year-old student with documented mental health issues launched that April 2007 attack with weapons he bought legally in Virginia.
In response, Congress passed a law that expanded the federal screening database for potential gun purchasers to include more than 2 million individuals who are barred from owning them due to felonies or mental illness.
Several mass shooting incidents during the late 1980s and early 1990s using assault rifles prompted Congress to pass a federal ban of assault rifles in 1994 - including a January 1989 shooting in which a drifter used an assault rifle to kill five children and injured 29 at a Stockton, Calif., school playground.
Congress included the ban on assault weapons in the 1994 crime bill signed by President Clinton. The ban has not been reauthorized since its expiration.
Passing such laws has become more difficult in recent years.
For example, there was no federal legislation following the 1999 mass killing at Columbine High School in Littleton, Colo., although several members of Congress introduced a variety of gun-related bills. That has been true following the January 2011 shootings in Tucson, in which six people were killed and then-Rep. Gabrielle Giffords, D-Ariz., was shot in the head, and the July 2012 shooting in a crowded movie theater in Aurora, Colo.
Friday's shooting could be a "game changer" when it comes to passing new gun laws, said Robert Spitzer, a political scientist at the State University of New York-Cortland and an expert on the politics of gun control.
"I put it on the side of being a slim possibility for a couple reasons - first because of the uniquely horrific nature of this particular shooting," Spitzer said. "All of these mass shootings are terrible but this shooting in particular seemed to be uniquely disturbing to Americans."
Spitzer said measures that could be passed would be "relatively small bore" and could include better record keeping and documentation to keep guns out of the hand of people with mental illnesses, restricting large-capacity bullet magazines, regulating assault weapons and Internet sales of guns and ammunition.
President Obama should use his power and issue an executive order to help tighten and provide resources for some of the current regulations to be implemented, including some of those in the law that President George W. Bush signed in January 2008.
Rep. Carolyn McCarthy, D-N.Y., a longtime advocate for gun safety, told CNN that Obama should use his power and issue an executive order to help tighten and provide the resources for some of the current regulations to be implemented - including some of those included in the 2008 law signed by Bush.
McCarthy's husband, Dennis, was killed and her son, Kevin, severely wounded in a December 1993 shooting on a commuter train on New York's Long Island Railroad. She was elected to the House in 1996 and was the author of the law passed after the Virginia Tech shooting.
"The problem with that (law) is it that there has never been enough money there to have all the courts, anybody that's been adjudicated through the courts, whether for any crime that would already basically not allow someone to own a gun to be put into the...instant background check system, so that's something he can do," McCarthy said.