While many questions remain about what motivated the killer in Friday's mass shooting in Connecticut, one thing is becoming increasingly clear -- the tragedy will re-ignite and further fuel a major debate over gun control legislation in Washington.
President Obama, without endorsing any specific proposal, hinted at Sunday night's vigil that he would enter that debate with vigor.
"We can't tolerate this anymore. These tragedies must end, and to end them, we must change," Obama said. He said "no set of laws can eliminate evil from the world ... but that can't be an excuse for inaction."
The calls for new national gun control measures emerged swiftly after reports first surfaced Friday of the shooting that claimed 26 lives, in addition to that of the gunman.
At the same time, the case is still being investigated and it's unclear whether any gun control legislation could have prevented the tragedy. While some are calling for new gun laws, there is also a growing call to examine, comprehensively, the culture in America that is producing these shocking bursts of violence.
Sen. Joe Lieberman, I-Conn., on "Fox News Sunday," called for a "national commission" looking at "violence and the entertainment culture" -- at video games, at movies, and asking whether they are causing "vulnerable young men, particularly, to be more violent."
Sen. Dick Durbin, D-Ill., endorsed the idea.
Durbin, though, was also among those calling for new scrutiny of America's gun policy.
While typically those calls are muted in the immediate aftermath of such a tragedy, the fact that most of the victims were children appeared to drive the eagerness among those in Washington to shift to the policy debate as soon as possible.
The election behind him, Obama on Friday called for "meaningful action."
White House Press Secretary Jay Carney said Monday that the issue will require a "comprehensive solution" involving gun control and other measures.
What form that action could take remains to be seen. Democratic lawmakers have already gravitated toward a few specific proposals.
On the more sweeping end, Sen. Dianne Feinstein, D-Calif., said Sunday she will introduce on the first day of the next session a de facto renewal of the assault-weapons ban that expired in 2004. She said the bill would also ban high-capacity clips.
On Monday, Feinstein announced details of the bill, including that it would stop the sale of more than 100 assault weapons but protects gun owners by exempting more than 900 specific hunting and sporting weapons.
The bill more specifically stops the sale, transfer, importation and manufacturing of more than 100 specifically-named firearms and certain semiautomatic rifles, handguns and shotguns that can accept a detachable magazine. It also applies to semiautomatic rifles and handguns with a fixed magazine that can accept more than 10 rounds.
In addition, the bill stops the sale, transfer, importation and manufacturing of large-capacity ammunition feeding devices capable of accepting more than 10 rounds.
Lawmakers are also talking about closing the so-called "gun show loophole," which allows people to buy weapons at gun shows without a background check.
And some officials are discussing more incremental measures. Rep. Carolyn McCarthy, D-N.Y., one of the most vocal gun control advocates on the Hill, endorsed the assault-weapons ban and the closure of the gun-show loophole, but also is suggesting a change to require a background check for private gun sales. And, in a letter to Obama on Sunday, she called for requiring federal agencies to share information gleaned from background checks.
Gun control opponents have kept their criticism mostly reserved in the wake of the Connecticut shooting, but they are sure to pipe up should legislation hit the floor next year.
Rep. Louie Gohmert, R-Texas, on "Fox News Sunday," noted that stricter gun control does not necessarily mean crime rates will go down.
"Washington, D.C., around us ought to be the safest place in America, and it's not. Chicago ought to be safe. It's not, because their gun laws don't work," Gohmert said.
He said lawmakers should "look at the facts."
Gohmert said he wishes the principal at Sandy Hook Elementary School were armed so she could have taken "his head off before he can kill those precious kids."
Obama, though, expressed the sentiment that lawmakers need to act to rein in guns, considering the rash of mass shootings that have occurred since he first took the oath of office.
"If there is even one step we can take to save another child, or another parent, or another town, from the grief that has visited Tucson, and Aurora, and Oak Creek, and Newtown, and communities from Columbine to Blacksburg before that -- then surely we have an obligation to try," Obama said, referencing the locations of past mass shootings.
He said that in the coming weeks, "I will use whatever power this office holds to engage my fellow citizens -- from law enforcement to mental health professionals to parents and educators -- in an effort aimed at preventing more tragedies like this."
The shooting also has drawn more moderate members into the debate. Sen. Joe Manchin, a West Virginia Democrat and member of the NRA, told MSNBC on Monday that gun control legislation should be discussed.
New York Mayor Michael Bloomberg, on NBC's "Meet the Press," said Obama should make gun control "his No. 1 agenda," speaking specifically about the assault-weapons ban.
"I don't think the Founding Fathers had the idea that every man, woman and child could carry an assault weapon," he said.
Bloomberg discussed gun control during an event in New York City Monday afternoon. On Capitol Hill, Senate Democratic Leader Harry Reid on the Senate floor Monday also called for a discussion on gun control.
The Senate observed a moment of silence for the Connecticut victims Monday afternoon. There will also be a moment of silence in the House on Monday evening.