The debate over potential new gun laws turned raw and tearful on Wednesday as a key Senate committee held hearings on an assault weapons ban backed by President Barack Obama.
"Jesse was the love of my life," said Neil Heslin, who broke down and cried as he told lawmakers about his son, Jesse Lewis, who was 6 years old when he was killed at Sandy Hook along with 19 other children.
Standing on an easel were two photos of Jesse, one as a young boy and the other as a toddler, cradled in his dad's arms. His father struggled to read his testimony, his voice cracking and sometimes fading to a near whisper as he told the committee that Dec. 14, 2012, was the saddest day of his life.
The emotional scene unfolded as the Senate Judiciary Committee met to discuss the potential assault weapons ban, part of a package of new gun laws that Obama is pushing for in the wake of the Newtown, Conn., shootings.
"Those weapons were used in a battlefield in Vietnam. They were used in the Persian Gulf, they were used in Afghanistan, in Iraq. The sole purpose is to put a lot of lead on a battlefield quickly," Heslin said of guns like the one Adam Lanza used in the Newtown elementary school massacre.
Tempers had already flared earlier in the hearing, as Republican Sen. Lindsey Graham clashed with Edward Flynn, the Milwaukee police chief. Graham was focused on limited prosecution of background check violations -- a reality that Republicans have highlighted as evidence that it would be more effective to enforce laws already on the books than to write new ones.
"We don't chase paper, we chase armed criminals," Flynn snapped back.
As senators discussed the ban, Vice President Joe Biden at the White House urged action on guns.
"The public mood has changed. The excuse that it’s too politically risky to act is no longer acceptable. We cannot remain silent," Biden said.
In the audience at the hearing was a group of supporters and friends from Newtown who offered Heslin quiet encouragement -- many crying along with him as he testified.
Before the hearing, they spent Tuesday on Capitol Hill lobbying members of Congress, meeting with Sen. Joe Manchin, W-Va., and staffers with Sen. Kay Hagan, D-N.C. They spent over an hour with Senate Majority Leader Harry Reid, D-Nev., and also met with House Majority Leader Eric Cantor.
They learned firsthand just how politically difficult an assault weapons ban would be.
"We appreciate what you do, more and more, seeing those meetings," Newtown resident Shelley Northrop told Sen. Chris Murphy, D-Conn., who with fellow Connecticut Sen. Richard Blumenthal stopped to talk quietly with the group from Newtown before the hearing began. Northrop was explaining to Murphy just how difficult it all seemed to get anything done.
"It's all tactical. Here, it's all tactical," Murphy told her.
He was being more diplomatic than Republican Sen. John McCain was last week, when he told the mother of a victim of the shooting in an Aurora, Colo., movie theater: “I can tell you right now you need some straight talk. That assault weapons ban will not pass the Congress of the United States," McCain said.
The Senate Judiciary Committee does plan to take up the assault weapons ban, possibly as soon as Thursday. Reid, the majority leader, has pledged to allow a vote on the floor on the measure, and even pro-gun rights Republicans are publicly supportive of doing so.
"I couldn't agree more, I think we should take legislation like this up and get on record and make our respective cases," Graham said at the hearing.
The vote is a key part of the political calculus on gun laws, because it could help give some members cover to vote for the legislation that Democrats privately say could actually pass: universal background checks and new gun trafficking statutes.
But in recent days, the ongoing negotiations on a background check bill have slowed, with Democrats and Republicans at odds over how to keep track of private gun purchases.
Democrats want to require private gun sellers to keep records of who they've sold guns to so they can be traced if they're used in a crime. Republican Sen. Tom Coburn, who's been negotiating, is opposed to that requirement because he says it could lead to a database of all gun owners.
That's prompted Democrats, led by Manchin, to reach out to other moderate Republicans who might be willing to sign on, including McCain and Sen. Susan Collins of Maine.
Both Collins and McCain met with New York City Mayor Michael Bloomberg on Wednesday to discuss gun control, and McCain said Tuesday that he has been involved in the negotiations.
"I've been talking to Sen. Manchin and others," McCain said Tuesday, though he emphasized that he has "only been peripherally involved."
Already involved in those talks is Illinois Republican Sen. Mark Kirk, who also met with Bloomberg on Wednesday. Bloomberg has already spent millions from his personal fortune to defeat pro-gun candidates in his bid to expand gun control; the billionaire also met with Reid on Capitol Hill.
NBC's Carrie Dann contributed to this report.