Push for new gun control regulations sparks fiery debate.
Vice President Joe Biden kicked off the public campaign for universal background checks and a ban on assault weapon sales on Thursday.
"Newtown has shocked the nation. The carnage on our streets is no longer able to be ignored," Biden told the U.S. Conference of Mayors.
Big city police want a gun buyer database in Washington.
"90% of our guns come from out of state. That's why we need a national approach," says New York City Police Commissioner Ray Kelly.
Still, key Congressional Democrats could oppose the president.
Senate Majority Leader Harry Reid, who voted against the 1994 assault weapons ban, says a new one can't pass Congress.
West Virginia Democratic Senator Joe Manchin questioned the right to own assault weapons after the Newtown massacre.
Now Manchin says he's "disappointed that the President did not recommend the creation of the national commission on mass violence."
National Rifle Association president David Keene wants the focus on the shooters.
"We need to find ways to get at the root cause of these kinds of violence and keep firearms with 10 round magazines, 20 round magazines, whatever, out of the hands of the kinds of people who involve themselves in this kind of activity, and they are invariably severely mentally ill," he says.
But the NRA is resisting universal background checks.
"If you can get a record of who owns firearms then the government can force them to sell those guns back to the government. That's basically confiscation," Keene argues.
Public opinion is divided as well.
The latest NBC News/Wall St. Journal poll finds the NRA has not lost support since Newtown.
The organization has a 41% approval rating, with 34% disapproval.