Five years ago today a lone gunman walked in to Sandy Hook Elementary School in Newtown, Connecticut and killed 20 children and six staff members. The tragic shooting shocked the nation and prompted widespread outcry for stricter gun laws.
Since then, Congress has done little to crack down on guns, something Sen. Richard Blumenthal (D-CT) laments.
"This time of year ought to remind us that we're failing in our obligation," he said in an interview.
"I say the same thing today that I said that day: the world is watching whether we act and so far, Congress has been complicit by its inaction," he added.
Lawmakers have proposed dozens of gun control measures to strengthen background checks, ban bump stocks and renew the ban on assault rifles that expired in 2004, but none of them became law.
The House of Representatives has been under Republican control since 2012, the year of the shooting at Sandy Hook. None of the gun control measures proposed in the House made it out of committee.
In April 2013 the Senate took up a bipartisan proposal from Sens. Joe Manchin (D-WV) and Pat Toomey (R-PA). The Manchin-Toomey Amendment would have required background checks for some private gun sales. The amendment was defeated when it couldn't garner enough votes to defeat a filibuster.
Last week however, the House passed a bill that would expand concealed carry by allowing concealed weapon permit holders to legally carry hidden firearms across state lines. The concealed carry measure was combined with a bipartisan bill to strengthen background checks. That measure would punish agencies that fail to report relevant criminal information about individuals that would prevent them from purchasing guns. It was proposed in the wake of a shooting at a church in Sutherland Springs, Texas, earlier this year after it was discovered the gunman had been convicted on domestic violence charges but was still able to purchase a gun because the Air Force failed to report the information to the National Instant Criminal Background Check System (NICS).
While Congress has been slow to pass federal legislation on guns, state gun laws have changed a lot since Sandy Hook.
Since 2012, states have passed 210 laws to address gun violence. Most of those strengthen background checks for gun purchases and for concealed carry permits. Many of those were a result of referendums and ballot initiatives.
But states have also pushed to make it easier for people to carry concealed firearms, which gun rights advocates say is a more effective way to prevent mass shootings.
Fourteen states now allow residents to carry concealed firearms without a permit. In 2012, the year of the Sandy Hook shooting, it was only four.
And some cities are encouraging teachers and faculty to arm themselves in order to protect students.
"We're seeing more and more states now actually pursuing this model of encouraging teachers, encouraging principals, by allowing them to be armed at the school in the eventuality that there's a mass shooter that they would be able to intervene and save lives," said Erich Pratt, executive director of Gun Owners of America.
Although legislation has been confined to the states, experts say that the national conversation around gun laws has grown much louder and has impacted American politics in a big way.
"One of the places that we've seen tremendous change is in how candidates for office are using this issue," said Chelsea Parson, vice president for guns and crime policy at the Center for American Progress.
"This used to be an issue that progressive candidates would stay as far away from as possible because it was just deemed a third rail and it was deemed an issue that you just can't win on, you can't spin it in a way that will help you," she said. "It has now become an issue where progressive candidates for office are fully endorsing common sense proposals to prevent gun violence as a core part of their platform. That was completely unheard of five years ago."
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