Following violent counter protests at a white supremacist rally Saturday, authorities at Stone Mountain say they are investigating ways to "prevent or control" future rallies when public safety is an issue.

But park spokesman John Bankhead, a veteran of decades of such protests as spokesman for the Georgia Bureau of Investigation, said the park’s options are limited since federal courts have long ruled that protest groups have a right to free speech.

Stone Mountain isn’t alone in wrestling with this issue.

Earlier this month, police denied a permit for an anti-Islamic protest where the organizers threatened to burn a Koran across from the State Capitol. Officials did not offer a reason for denying the permit but did send a number of alarming emails about the planned protest to state employees and contractors in the area, with reassurances that it would be properly policed.

Despite being denied a permit, the protest group, made up of two men and some posters, showed up anyway and were allowed to have their event.

Anthony Kreis, an instructor in the University of Georgia’s School of Public and International Affairs, said said governmental entities must meet a two-pronged test when attempting to reign in public speech.

First, the entity can set policies and rules governing how, when and where protest groups can hold their rallies. But Kreis said those rules have to be “content neutral,” meaning the same rules apply to everyone, no matter what they wish to say.

“The second part of that is those rules, no matter how neutral they are, can’t burden speech more than necessary,” he said.

That second part is perhaps the tougher test.

In 2014, the U.S. Supreme Court ruled that a Massachusetts law creating a 35-foot buffer around abortion clinics improperly limited speech near the facility. During Saturday's protests at Stone Mountain, police kept counter protesters more than 150 yards away from the white supremacist rally they wanted to "shut down.