"We're going to need your courage and strength," Blumenthal said.
The message from political leaders and others, Cox said, "has become very clear — act now, grow your numbers, get to Washington."
But the question remains — can another mass shooting be prevented? After all, Sandy Hook Elementary School was locked on that horrific morning; Lanza shot his way in. The National Rifle Association has called for armed guards in every school.
"I will say I feel safe in Sandy Hook and in Newtown," said Len Strocchia of Newtown, whose daughter, now 13, attended Sandy Hook Elementary School. "I think the school was safe. I don't think there's much you can do to stop somebody hell-bent on entering a school and committing murders. I would not want an elementary school turned into a bulletproof prison for our kids."
Gratitude is the overwhelming sentiment among all Sandy Hook Elementary parents whose children survived the massacre. Eric Weiss said his son, a second-grader, was in a classroom near one of the rooms where children were killed. The boy listened to his teacher and escaped unharmed.
"We're forever in their debt," Weiss, who also has a daughter in afternoon kindergarten, said of the school staff. "You can't ask more from somebody. You put your children in someone else's custody, you would hope they would react the way our teachers did."
"I'm just very appreciative that my children are with me," he said.
The voices of parents whose children were killed would be a powerful addition to Newtown United, but Cox said it's too early to approach them.
"We are here for the families," said Cox, the editor of Reuters' financial commentary website, Breakingviews.com. "We're building a structure and a platform for the families when they are ready to express their views about how to meaningfully reverse the tide of gun violence."
"We know," he said, "that our pain is nothing compared with theirs, so we can focus our energy to make Newtown count for something."
Newtown United members sign communications to each other with the letters FTF, "For the Families."
Visit the group's facebook page at http://www.facebook.com/NewtownUnited.