It has happened before: Aurora. Columbine. Tucson. Virginia Tech.
But, this time, the White House and a growing number of Democratic lawmakers on Capitol Hill promise it will be different. This time, they say, things will change.
In Washington and around the country, the legacy left by the 26 people -- 20 of them young children -- slaughtered in a school shooting on Friday in Newtown, Connecticut, might indeed be meaningful legislative reform.
Over the past few days, several lawmakers have promised to introduce or reintroduce gun control legislation, ranging from a reinstatement of a federal ban on assault weapons to banning the sale of high-capacity magazines.
On Monday, there was a moment of silence on the floor of the U.S. Senate to honor those killed at Sandy Hook Elementary School. The chamber's chaplain called on lawmakers to "act promptly." The House also observed a moment of silence Monday evening.
"To me and to others, this one feels different," said Jon Vernick, co-director of the Johns Hopkins Center for Gun Policy and Research. "Maybe because of the timing, maybe because of the victims, 20 young children. Maybe it's because we have a president who has been re-elected who is not going to be running again. That doesn't mean those political obstacles aren't still there, but it does feel different."
Friday, just after the shooting, White House spokesman Jay Carney said President Barack Obama was willing to consider reinstating the assault weapons ban that expired in 2004.
On Sunday, in his remarks at the vigil in Newtown, Obama hinted that he'll "use whatever power this office holds to engage my fellow citizens ... in an effort aimed at preventing more tragedies like this. Because what choice do we have?"
On Monday, the White House inched closer to addressing what Carney called a complex problem. And Tuesday afternoon, Carney said the president now supports Sen. Feinstein's intended effort to reinstate the assault weapons ban.
The most notable shift in tone comes from some conservative Democrats who have high rankings from the National Rifle Association for their pro-gun rights legislative stances.
Friday's shooting was a "game changer," tweeted Virginia Democratic Sen. Mark Warner, who'd previously received an "A" rating from the NRA.
"This awful massacre of our youngest children has changed us, and everything should be on the table," Sen. Joe Manchin, a conservative Democrat from West Virginia and "proud gun owner," said Monday in a statement. "We need to move beyond dialogue -- we need to take a sensible, reasonable approach to the issue of mass violence."
New Jersey Democrat Sen. Frank Lautenberg plans to reintroduce legislation in the next Congress that would prohibit the sale of high-capacity magazines, his office confirmed Monday. He and California Sen. Dianne Feinstein hail from states that advocates of gun control, such as the Brady Campaign to Prevent Gun Violence, say have some of the toughest gun restrictions.
Feinstein announced Sunday she'll reintroduce an assault weapons ban when Congress reconvenes in January.
Movement in the White House
Citizen-created petitions on the White House's website have netted thousands of signatures on both sides of the issue in just a few days. But the political reality is that crafting meaningful legislation is a tricky prospect.
The White House has said Obama supports reinstatement of a federal ban on assault weapons -- a position he took in the 2008 campaign but failed to press during his first term.
"It does remain a commitment of his," Carney told reporters Friday.
But later that day, an emotional Obama did not address the issue directly in a televised statement from the White House.
"We're going to have to come together and take meaningful action to prevent more tragedies like this, regardless of the politics," said Obama, the father of two girls.
A White House source told CNN that on Monday afternoon, Obama had discussions with White House senior staff, the vice president and several Cabinet members, including Education Secretary Arne Duncan, Health and Human Services Secretary Kathleen Sebelius and Attorney General Eric Holder to begin looking at ways the country can respond to the tragedy in Newtown.
The politics of guns
Obama largely avoided the issue of gun control during his first term.
He wrote an opinion piece two months after the 2011 assassination attempt on Rep. Gabrielle Giffords of Arizona, acknowledging the importance of the Second Amendment right to bear arms and called for a focus on "effective steps that will actually keep those irresponsible, law-breaking few from getting their hands on a gun in the first place."