CLARIFICATION: An earlier version of this story inadvertently misrepresented the prior gun-control position of Rep. John Yarmuth, D-Ky. He has always supported it.
Sen. Robert Casey, D-Pa., does not shy away from the "pro-gun Democrat" label. He has a B-plus rating with the National Rifle Association, a score docked only because he supported the confirmation of Supreme Court Justices Sonia Sotomayor and Elena Kagan, and he represents a state with a strong hunting tradition.
But for Casey, last month's massacre at Sandy Hook Elementary School was a pivotal moment. Casey said he found himself emotionally rocked by the Newtown, Conn., tragedy in a way that was different from the mass shootings in Aurora, Colo., this summer or in Tucson, Ariz., last year.
"It hit me in a way that the others didn't, and that's terribly unfair to those other families, but I would not be honest if I said otherwise. This hit me in a way that no other incident has in years," Casey said in an interview. "I found myself being more emotional about this than virtually anything I've ever worked on."
Its emotional weight has forced him to reconsider two gun-control provisions: banning assault weapons and limiting high-capacity ammunition.
"So there are two votes, and because of the weekend and what I saw happening in Connecticut , it caused me in a very deeply and emotional way, as I guess it did everyone, to seriously consider voting for those," he said. "And under normal circumstances, I'd be on the other side."
Casey's introspection isn't a unique tale among normally pro-gun Democrats. In a high-profile acknowledgment, Sen. Joe Manchin of West Virginia said that, at least for now, he is open to reconsidering measures he once opposed. Rep. John Yarmuth of Kentucky has supported gun-control measures in the past, but in an impassioned speech made it clear he would no longer stay silent about the need for such legislation.
"We woke up Saturday morning to a different nation than we were 24 hours earlier," said Rep. Nick Rahall of West Virginia, another pro-gun Democrat who has said he is willing to consider banning high-capacity clips.
For now, measures to limit guns might be gaining popularity after the Sandy Hook shooting. A plurality of 49 percent of Americans say that it's more important to control gun ownership than to protect the rights of gun owners, according to a poll released on Dec. 20 by the Pew Research Center. Forty-two percent say the opposite. It's the first time since President Obama took office that Pew has found that more American prioritize gun control over protecting gun-ownership rights.
It's not just congressmen who have reexamined their opinions, according to Rep. Tim Holden of Pennsylvania, a normally pro-gun Democrat whose campaign received a contribution from the NRA's political arm during the 2012 cycle. "I was just talking to my brother a couple of hours ago, and he's a much more avid hunter than I am; and he was, like, something's gotta happen here," he said.
Holden, who lost his primary to a more liberal Democrat, said he would likely support reinstating a nationwide assault-weapons ban if he were still in office next year. Holden, in fact, voted for an assault-weapons ban in 1994, a vote many Democrats continue to believe helped fuel the GOP's takeover of the House during that year's midterm elections.
Holden said he took a "political beating" for the vote but nonetheless survived. Gun laws are a difficult issue for many Democrats, especially those who represent culturally conservative districts. Out of political necessity, they have to distinguish themselves from liberals such as House Minority Leader Nancy Pelosi of California. And few issues offer a greater opportunity to do so than opposing gun control, an issue that resonates viscerally among most voters.
Rep. Mike Thompson, D-Calif., is familiar with the dilemma. The Vietnam War veteran and avid hunter, who supports reinstating the assault-weapons ban, was just named head of a House Democrats' task force on gun violence. In an interview, he made clear the importance of assuring fellow citizens that the government doesn't plan to take away their guns.
Asked how he can persuade his colleagues to support gun control, he responded succinctly: "Well, we can start by not calling it "˜gun control.' "
"I think there are Americans who are concerned that any of this discussion will lead to them losing their right to have firearms, what I call "˜legitimate firearms for legitimate purposes,' " said Thompson. "I believe people who are law abiding and mentally stable should be able to have those types of firearms."
Rep. Bennie Thompson, D-Miss., is an active hunter in a poor rural state where everyone hunts. He has an F grade from the NRA, but he is likely to chair the House Sportsmen's Caucus next year, and he was listed in September as one of eight "surprisingly pro-gun Democrats" by Guns and Ammo.
"I've been associated with guns and hunters ever since I was 8 years old. I live in a community of 500 people," Bennie Thompson said. "I'm taking my 7-year-old grandson hunting on Saturday if we can get out of here."
Thompson has many friends who are NRA members, and they always question his ratings when they get their scorecards. "They call and ask me, "˜You're a better marksman than most in Congress, but you're getting an F,' " he said. But he says the NRA rankings are based on odd votes that have nothing to do with his passion for hunting. "I don't need assault-style weapons," Thompson said.
Not all Democrats are conceding that gun-control measures need to be taken. Senate Finance Committee Chairman Max Baucus, D-Mont., a longtime advocate of gun owners, isn't making a decision right away on where he stands, despite being hounded with questions. He said he needs to hear from his constituents before he can decide whether to vote for an assault-weapons ban or other gun laws that could be considered in the Senate.
"I am listening to my people, my bosses, and I do believe, too, that whoever suggested a commission made a good suggestion," Baucus said, referring to Vice President Joe Biden's commission on reducing gun violence that Presideent Obama called for. Baucus shrugged off a question about the "conversions" of some of his pro-gun colleagues, such as Casey or Manchin, who has said "everything should be on the table" in a gun conversation. "I'm not going to get into that."
Elahe Izadi contributed contributed to this article