The deaths of 20 children in a devastating shooting rampage at an elementary school in Connecticut reignited the debate over gun laws that until now has yielded little change.
After the massacre at the Sandy Hook Elementary School, President Barack Obama appeared on television with tears in his eyes to make an emotional plea for "meaningful action" after the latest outrage.
"As a country we have been through this too many times," Obama said, mentioning earlier shooting massacres, in Colorado, Oregon and Wisconsin.
Earlier White House spokesman Jay Carney declined to discuss the political fallout.
He said it was a day "to feel enormous sympathy for families that are affected".
But congressman Jerrold Nadler, a Democrat, immediately responded: "If now is not the time to have a serious discussion about gun control and the epidemic of gun violence plaguing our society, I don't know when is.
"Yet another unstable person has got access to firearms and committed an unspeakable crime against innocent children.
"We cannot simply accept this as a routine product of modern American life," he said.
"I am challenging President Obama, the Congress, and the American public to act on our outrage and, finally, do something about this."
Obama's presidency has been marred by several mass killings since 2009, including a 2011 attack on Democratic congresswoman Gabrielle Giffords and a rampage at a Colorado movie theatre in July that left 12 dead.
After a massacre this (northern) summer that killed six people at a Sikh temple, the White House rejected the idea of new gun control legislation.
Obama's position was that the administration would do everything in its power to keep guns out of the hands of criminals and unstable individuals, while protecting Americans' constitutional right to bear arms.
The constitution's Second Amendment is defended tooth and nail by the US gun lobby, which has been successful in blunting past drives to restrict the sale of high-powered weapons.
To change the laws, Obama needs Congress to act, and so far the Republican opposition has blocked all reforms of the federal gun laws.
The US media has revived the debate, as it did after the killings in Aurora, Colorado and earlier this week after three people were killed in a shooting at an Oregon shopping mall.
But defenders of the Second Amendment insist that restrictions on the sale of semi-automatic weapons is not the solution.
"There's a good side of guns and you can't forget about either," said Alan Gottlieb, the head of the Second Amendment Foundation.
"There was nobody in that school who was allowed to have a firearm to protect themselves or those children. And I find that to be deplorable.
"I'm sure the person who committed this horrible act knew he could go in and do it because no one else could have a gun.
"He didn't care about the law because he was going to break it anyway," he said.