"Shame on us," President Obama said Thursday, "if we've forgotten the kids killed at Newtown."
Still, his push for gun control is in trouble.
Fewer Americans want stricter regulation of firearms.
Rallies were held across the country Thursday, part of the push by New York Mayor Michael Bloomberg's DemandAction.org's for tougher laws.
The campaign includes TV ads featuring Newtown parents as well.
The goal: A ban of assault weapons and high capacity magazines and comprehensive background checks.
There were counter-demonstrations as well.
"It's my right to have this firearm and I don't have to defend, to show a need for this firearm to own it," shouted one man carrying an assault rifle at one rally.
After 20 kids died in the Sandy Hook Elementary massacre in December support for stricter gun control surged, but it's dropped 9 to 10 points in new polls.
President Obama tried to reawaken the outrage during an address at the White House.
"Why wouldn't we want to close the loophole that allows as many as 40% of all gun purchases to take place without a background check?" he asked.
On that least controversial proposal, backed by 80% in some polls, at least six senate democrats from conservative states could vote no.
Democrat Heidi Heitkamp of North Dakota said "We can go after and prosecute criminals without the need to infringe upon the Second Amendment rights of law-abiding North Dakotans."
That leaves a defeat in Congress on gun control looking more likely.
-- Steve Handelsman, NBC News, reports