It was three years ago this month that Wayne LaPierre, executive vice president of the National Rifle Assn., enraged gun-control advocates with his defiant assertion that more firepower was the solution to America's wave of mass shootings.
"The only thing that stops a bad guy with a gun is a good guy with a gun," LaPierre declared at a news conference one week after the shooting that left 26 people, including 20 children, dead at Sandy Hook Elementary School in Newtown, Conn. La Pierre suggested an armed security officer could have stopped the tragedy and called for garrisoning police in every school.
Today, those struggling to make sense of the nation's latest massacre face a vexing but unavoidable question: Was LaPierre right?
The murder of 14 people at a social services center in San Bernardino on Wednesday was a grimly familiar entry in America's growing ledger of shooting massacres. As the FBI investigates the assault as an act of terrorism, it has also become a flashpoint in the debate over what, if anything, can be done to stop such killings.
Among the most contentious aspects of that debate is the clamor by some for more police officers and armed security guards at potential target sites.
A spokeswoman for the Inland Regional Center — the sprawling facility for adults and children with developmental disabilities where the San Bernardino shooting occurred — disclosed on Friday that an unarmed security guard was on duty when the attack took place.
She said she did not know where the guard was when Syed Rizwan Farook and his wife, Tashfeen Malik, pulled up at the center's conference building in a black SUV, armed with rifles, pipe bombs and tactical vests, and opened fire on Farook's co-workers at a holiday party. The guard typically "roves the parking lot," said Leeza Hoyt, a public relations specialist hired by center officials.
Every shooting unfolds according to its own grisly logic, making speculation about across-the-board preventative measures risky. Gun-control advocates, along with many on the political left, have often dismissed arguments for more firearms in public places. They say the correct route to preventing shootings is restricting access to guns for would-be killers.
Yet others say recent gun massacres, as well as thwarted attacks, are adding weight to arguments in favor of fortifying crowded buildings and public places with armed personnel.
Dave Grossman, a retired Army lieutenant colonel and police trainer and who spoke at this year's NRA convention, said an armed security officer stationed at the site of the San Bernardino shooting could have made it much harder for Farook and Malik to carry out their plan.
"Absolutely an armed guard on site would have greatly reduced the probability that they would have done it, and it would have greatly reduced the likelihood that they [would have] got the body count that they did," Grossman said.
He pointed to the May assault on a Texas conference center hosting a deliberately provocative contest for cartoons of the Muslim prophet Muhammad. Two men equipped with rifles, handguns and body armor were shot and killed by a local traffic officer after they opened fire at the entrance to the event. The only wound the gunmen inflicted was on an unarmed security guard, who was shot in the leg.
Some evidence also indicates that armed guards, while present, can prevent attacks from happening. A gunman who killed three at a Planned Parenthood clinic in Colorado just days before the San Bernardino shooting didn't enter the facility until after a private security guard had gone off duty.
Yet such anecdotes are far from conclusive, said Pete Blair, a criminal justice professor at Texas State University who coauthored a 2014 study of "active shooter incidents" — defined as shootings still in progress when officers respond — for the FBI.
Blair said "there's not any large-scale evidence" proving that armed guards deter or reduce casualties at shootings, despite the plain-spun logic of the "good guy with a gun" argument.
"We've seen most of these shootings occur at places that don't have armed security guards," Blair said. "But then most places in the country don't have armed security guards, so it's hard to prove that that's the decisive factor."
An armed school resource officer was actually present at one of America's worst mass shootings, the Columbine High School massacre of 1999. The officer, a Jefferson County sheriff's deputy, was outside the school when students Eric Harris and Dylan Klebold began their attack and was unable to prevent them from killing 12 students and one teacher, although he fired his gun from a distance at Harris.
Laura Cutilletta of the Law Center to Prevent Gun Violence, a San Francisco-based group that advocates for stricter gun laws, said she saw no problem per se with the presence of armed guards, so long as they have appropriate training.
"I think if it were extremely limited to law enforcement only, and security guards with a very high standard of training, that's one thing," she said.
The problem with the NRA's argument, she asserted, is that it is a thinly veiled call for ordinary citizens — rather than trained public-safety professionals — to buy and carry guns. (A spokeswoman for the NRA declined to comment on the group's position on armed guards in public places.)
If widespread gun possession led to fewer shootings, Cutilletta said, "you would think that America would be the safest country on Earth, given how many guns we have in the population. And the truth is the exact opposite."