Many of the first responders have remained out of the public eye in the weeks since the tragedy, keeping their personal grief and emotional trauma private.
"The excuse that it's too politically risky to act is no longer acceptable. We cannot remain silent," Biden said in an impassioned plea. "We have to become the voices of those 20 beautiful children who 75 days ago were killed. They can't speak for themselves.
"You know better than any elected officials," the vice president said. "We have to speak for the more than 2,000 people who have died at the end of a gun just since Newtown -- 2,000 Americans in 75 days."
The vice president is also meeting with New York Mayor Michael Bloomberg, another gun control advocate, to discuss the administration's gun violence proposals. He acknowledged differences of opinion in how to best address the epidemic of gun violence, but said attorneys general are well-positioned to bridge a partisan divide.
"All of you, unlike any other elected official in your state, are cloaked with both a moral and political credibility that no other office holds," Biden said. "Each of you are able to operate in an area that is not viewed as a partisan bloodbath.
"I need your advice and I need your help, and I mean that sincerely," he added. "No one has ever doubted that I mean what I say, the problem is I tend to say all that I mean, and that gets me in trouble."
One of the most contentious moments of today's hearing highlighted the difficulty of passing any gun control legislation. Sen. Lindsey Graham, R-S.C. asked witnesses about prosecutions for those who foiled current legislation that requires background checks for most gun purchases.
An increase in background checks to include people who buy weapons from gun shows and from individuals is one aspect of the gun control debate that has wide support. Graham said the existing laws should first be better enforced.
"If we're going to require background checks, it looks to me like we ought to start enforcing the law that's on the book," Graham said. "I'm a bit frustrated we say one thing about how important it is, but in the real world we absolutely do nothing to enforce the laws on the books."
Sen. Dianne Feinstein, D-Calif., who introduced the assault weapons ban, recounted the violence inflicted at a number of mass shootings involving assault style firearms as an example for why such kinds of weapons should be banned.
"That horrific event shocked our nation to its roots. And the pictures of these little victims brought tears to the eyes of millions of Americans. We are holding today's hearing because the massacre in Newtown was sadly not an anomaly," Feinstein said. "We cannot allow the carnage I have described to continue without taking action on what is a serious matter of public policy."
Sen. Chuck Grassley, R-Iowa, argued, that limiting the types of firearms people can purchase is not the way to stop criminals from committing acts of violence.
"When something has been tried and found not to work, we should try different approaches rather than reenacting that which hasn't done the job. There are vast numbers of gun-control laws in our country. Criminals do not obey them, but law-abiding citizens do. That tilts the scale in favor of criminals who use guns," he said.