A new advertising campaign seeks to end gun-free zones.

It's because that's where so many people are killed by people with guns.

Alan Gottlieb, the founder of the Second Amendment Foundation, which began the effort, said areas where landowners or property managers suspend the Second Amendment are "shooting galleries for maniacs."

"Without a self-defense option," Gottlieb said, "we are all at greater risk."

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The slogan on the ad is, "You're a sitting duck in a gun-free zone."

Gottlieb cited a report from the Crime Prevention Research Center finding that 98 percent of mass public shootings since 1950 occurred in places where citizens are prohibited from possessing firearms.

In Europe, it's worse, he said, where "every mass public shooting has occurred in a gun-free zone."

See the ad:

Gottlieb pointed out the schools, shopping malls, movie theaters and churches that have been targeted as examples of "gun-free zones."

The designation did not prevent tragedies.

They actually may have enabled crazed killers by making it impossible for the victims to fight back, his report said.

"Whether you’re talking about a high school in Florida, a theater in Colorado or a mall in Nebraska," he said, "the common denominator has been that they all prohibited firearms on the premises. Of course, in every case, that ban had zero effect on the shooters who took innocent lives. There are numerous other examples where the gun-free mindset has been worse than a failure, and history has provided us the grim casualty counts to prove it."

Not only are gun-free zones not a solution, he said, they actually pose an additional danger because "they prevent legally armed citizens from defending themselves and others, while creating the mere illusion of safety."

"For more than two decades," Gottlieb said, "the U.S. has perpetuated a false sense of security with gun-free zones. It's time to end this dangerous folly. Nobody wants to be a sitting duck in a maniac's shooting gallery."

The ad states: "Over the course of 18 years, 1998 to 2015, the CPRC found 2,354 attacks and at least 4,880 shooters outside the U.S. and 53 attacks and 57 shooters within this country.

"Ninety-eight percent of mass public shootings since 1950 have occurred in places where citizens are banned from having guns. In Europe, every mass public shooting in history has occurred in a gun-free zone."

Twenty years of gun-free zones have shown they are not the answer, the ad says.

"Truth is, they are an added danger."