THIS SUMMER when a gunman toting a Smith & Wesson semiautomatic rifle burst into a packed movie theater in Aurora, Colo., and murdered 12 people, America's leaders had little to offer survivors and angry citizens beyond their thoughts and prayers.
In a year when nearly 80 Americans have died in mass shootings, the banal evil of a man walking into an Oregon mall last week and killing two random shoppers was barely a blip on the media radar.
Even after the 2011 assassination try on U.S. Rep. Gabrielle Giffords that wounded her and claimed the lives of six bystanders, her Democratic Party - noted the political blogger Heather "Digby" Parton - "celebrates when she recovers enough to lead the Pledge of Allegiance at their convention - but never even [mentions] gun control."
But that was before Friday.
That was before the nation learned the unspeakably horrific details of how a 20-year-old gunman in a bulletproof vest shot his way into a Connecticut elementary school and used a .233 caliber Bushmaster semiautomatic rifle to kill 6- and 7-year-olds in a hail of bullets.
That was before Newtown.
And so as the flames of countless candlelight vigils still flicker in the December mist, two questions linger after the second-worst mass killing in U.S. history:
Is this what it took, this, the wanton slaughter of first-graders, to finally reach a tipping point, to finally start a national conversation about a runaway gun culture and the other causes of a level of violence that takes place in America like nowhere else in the industrialized world?
And if this is a tipping point, what would a solution even look like in a nation so deeply divided on the meaning of "the right to bear arms," and so mired in political gridlock?
Most experts say a mass killing of elementary schoolers could - and certainly should - lead to the first real political debate about violence and gun control since Congress passed the Brady Bill for handgun background checks and also for a time banned many assault rifles, in 1993-94.
"It is possible that this will be a turning point," said UCLA constitutional law professor Adam Winkler, author of 2011's Gunfight: The Battle over the Right to Bear Arms in America. "It seems that the anger that we've seen from people is greater than we've seen from other mass killings."
Indeed, this weekend's spontaneous outpouring of grief and anger certainly felt remarkable. At least 120,000 people signed a petition on the White House website urging President Obama to push Congress for tighter gun laws, an all-time record.
The first poll taken after the Newtown killings - a HuffPost/YouGov survey - showed 50 percent of Americans now backing stricter gun laws, a rare reversal after more than a half-century of mostly declining public support for firearms control. And many people felt an overpowering urge to do something, even if they weren't sure what.
"I just cried and cried and cried my eyes out," said Cecile Steinriede of Bala Cynwyd, a 45-year-old real-estate agent and mother of a 10-year-old.
On Saturday, she'd formed a group on Facebook called Philadelphians for Common Sense Against Guns, and on Sunday, she brought a dozen or so people to Broad Street south of City Hall, holding signs "Honk Against Gun Violence."
It's surprising that has taken so long. Not only have 15 of the world's 25 worst mass killings over the last half-century taken place in the United States, but the pace has been increasing, amid a rapidly rising rate of gun ownership. And a flurry of state laws relaxing gun curbs - like the one passed by Michigan lawmakers last week that would even allow concealed weapons in schools.
And lost sometimes in the outrage over mass shootings is the daily drumbeat of urban carnage in cities such as Philadelphia, where roughly 80 percent of the roughly 320 homicides so far in 2012 - on pace to be the most in five years - are committed at the barrel of a gun.
There are two key facts that often get buried in the gun debate. Restrictive laws can make a difference - as happened in Australia. It experienced some 13 mass killings in the generation before a 1996 gun-control law that banned some rapid-fire weapons and included gun buybacks and other features. There has been just one mass killing since then, and murder and suicide rates dropped sharply.
Also, a conservative myth that arming more citizens would stop mass murderers is exactly that, a myth. A new Mother Jones probe of 62 U.S. mass killings could not find one that was stopped by a civilian using a gun.
But in an era in which the National Rifle Association funds politicians 10 times as much as the gun-control lobby and turns out a dedicated cadre of single-issue voters, both Obama and his GOP rival Mitt Romney were loathe to even mention guns in the 2012 race. It was reported that gun restrictions such as tougher background checks were drafted by the U.S. Justice Department in 2011 but then shelved because of politics.
"The political climate is different now than it was after Gabrielle Giffords, different than it was after Aurora," argued UCLA's Winkler, noting that a number of NRA-backed candidates, including Romney, were defeated in November.
Shira Goodman, executive director of the gun-control group CeaseFirePA, said there's increased optimism over a planned push in Washington in January to restore the assault-weapons ban.
Meanwhile, she said her group will push in Harrisburg for background checks of private gun sales and to fix problems with mental-health records, while working to prevent lax concealed weapons laws in other states from holding sway in Pennsylvania.
"People really want to do something," Goodman said, describing the people she met at a candlelight vigil on Saturday.
But most experts agree it's clear that the horror that transpired in Newtown is about more than just guns, and comes as America is neglecting issues around mental health.
"We have to destigmatize people that have mental health-problems," said James Peterson, a Lehigh University professor who studies youth culture. He decried Medicaid reductions and other funding cuts for mental-health programs, and urged more openness in classrooms and churches.
Peterson also said there needs to be more conversation about the wider embrace of violence in American culture, from fighting two lengthy wars overseas to gun-happy video games - whose impacts on teen health are just now being studied.
Still, this weekend's many calls for action were tinged with weariness.
Too many times, America has been here before.