Francine Wheeler -- whose son, Ben, was one of 20 children and six staffers killed Dec. 14 at Sandy Hook Elementary School -- used the occasion to ask Americans to call on their representatives in Washington to enact "commonsense gun responsibility reforms that will make our communities safer and prevent more tragedies like the one we never thought would happen to us."
"When I packed for Washington on Monday, it looked like the Senate might not act at all," Wheeler said, appearing with her husband to deliver the address.
She said things changed after Obama spoke in Hartford, Conn., and a group of Newtown parents met with U.S. senators -- with 69 senators voting Thursday to debate legislation.
"But that's only the start," she said. "They haven't yet passed any bills that will help keep guns out of the hands of dangerous people. And a lot of people are fighting to make sure they never do."
Wheeler said thousands of Americans have been killed in gun violence in the four months since the Newtown massacre.
"Please help us do something before our tragedy becomes your tragedy," she said.