In the wake of recent mass shootings several law enforcement leaders are now encouraging CCW. Is this an idea whose time has come?

...[s]everal law enforcement authorities said Thursday that there is a case to be made that licensed gun owners may act as deterrents to mass shooters. “I think after Paris, and as we learn more about this event [in San Bernardino] we need to be nimble enough and pragmatic enough to recognize that there’s definitely a small number of documented mass-casualty shootings that have been ended by off-duty law enforcement and civilians,” said Eugene O’Donnell, a professor at the John Jay College of Criminal Justice in New York. A former police officer, Mr. O’Donnell said about half of mass shootings are finished before the first officer arrives, given that “these are people that are coming in to kill.”
“They’re coming in to kill as many people as they can, as quickly as they can, so the old model — the police would get there, they would cordon the place off, you could talk people through — a large number of these events are going to be over before the cops get there,” Mr. O’Donnell said. Ulster County Sheriff Paul J. Van Blarcum encouraged residents of his New York jurisdiction Thursday to carry their firearms if licensed. “In light of recent events that have occurred in the United States and around the world, I want to encourage citizens of Ulster County who are licensed to carry a firearm to PLEASE DO SO,” Sheriff Van Blarcum wrote in a Facebook post. The sheriff, whose county is about two hours north of New York City, also reminded retired and active-duty police officers to “please carry a weapon whenever you leave your house.”
http://www.washingtontimes.com/news/2015/dec/3/armed-citizenry-seen-as-mass-shooting-terrorism-de/