Meetings of his task force on gun violence twice were interrupted by news of school shootings, Vice President Joe Biden told House Democrats on Wednesday evening.
Biden used those instances to buttress the White House's agenda on the issue.
"When we were meeting with various groups to decide how to proceed, on two occasions in the middle of our meetings we got word that there had been additional shootings in schools," Biden said.
He continued, gesturing toward a House member, "The fourth day of our meetings - in your home state of California in Bakersfield, I get an urgent note, while we're deliberating - another school shooting. Thank God not nearly as extensive.
"Folks, you agree with me, I'm sure, enough is enough is enough. We have to stand up."
Biden was seeking to rally Democrats in Congress behind President Barack Obama's gun violence proposals at their retreat Wednesday evening. Obama had tasked his vice president with investigating the issue and proposing solutions after the deadly elementary school shooting in Newtown, Connecticut in December -- an instance of violence Biden brought vividly into his pitch.
He described how he envisioned the scene in Newtown where lay "those beautiful young children, six and seven years old, literally riddled -- riddled -- with bullet holes, lying in their classroom."
He described the parents searching for their children in the school parking lot and at the nearby fire station -- a sight, he said, which the country "witnessed the profound loss of not only those families but the profound loss that America suffered."
He described the personal devastation of losing a child. His one-year-old daughter died with his first wife in a 1972 car accident.
What emerged after the meetings from the White House was a set of executive actions which Obama said he and his administration would take, as well as a set of legislative proposals - some considered more feasible on Capitol Hill than others.
Their legislative actions include reinstating the ban on assault weapons, requiring background checks on all gun sales (rather than only on sales from federally licensed dealers) and restricting the size of gun magazines.
The assault weapons ban was passed in 1994 and expired a decade later. Biden said passing the 1994 ban was "tough."
"We lost the Congress immediately after that," he said, noting that Republicans won control of the House in the midterm elections. "Some attributed it to the difficult stance people had to take particularly on the assault weapons ban. People had walked away learning the wrong lesson from that, saying, you know what, it's demonstrable that it's too risky to take on some of this stuff because look what happened last time we did this."
Biden said concern that an electoral price would be paid has kept Democrats from voting for the ban.
"I'm here to tell you the world has changed. The world has changed since 1994. Public attitudes have changed since 1994," he said.
A CNN/ORC poll conducted in December found a majority of adults favored banning large ammunition magazines (58% support) and semiautomatic weapons (56%).
But the challenge for the White House would be getting those proposals through Congress.
Biden, who spent decades on the Hill himself, made an emotional pitch to the Democratic lawmakers, who would be important votes on any measures.
He told them of the "15-year-old Chicago girl who so proudly marched by me and the president and the rest of you on inauguration day leading with pride and promise her high school band, gunned down in a park just outside her school in broad daylight."
The vice president was referring to Hadiya Pendleton, who was shot at a park on Chicago's South Side.
Biden also criticized the idea of arming teachers and other school personnel, though he did indicate support for having a police presence within schools known as resource officers.
He spoke in favor of a federal gun trafficking law, increasing the number of police officers on streets and studying both mental health and the impact of violent video games.
Obama is set to speak at the Democratic lawmaker retreat on Thursday.