When Rick Santorum joined other GOP presidential hopefuls for a “national security” summit hosted by right-wing conspiracy theorist Frank Gaffney last weekend, it shouldn’t have been a surprise that they would encounter fringe conspiracy theorists in the audience, including one activist who asked Santorum a winding question about immigration, an imminent communist takeover and President Obama’s plot to nuke Charleston, South Carolina.

As we reported on Monday, Santorum responded to the activist’s accusation not by rebutting her conspiracy theory but by taking offense to her claim that Santorum, a former U.S. senator, had some responsibility for the congressional GOP leadership’s response to Obama’s immigration actions. He went on to label the president a “tyrant.”

The story of Obama’s purported plot to detonate a nuclear bomb in Charleston, which the questioner said occurred just “a few months ago,” has been circulating in far-right outlets for several years.

Essentially, the story goes that Obama planned to nuke Charleston as part of a false flag attack to build support for the U.S. entering the war in Syria or another conflict.

Dave Weigel posted a breakdown of the wild accusation, which unsurprisingly, involves “InfoWars” host Alex Jones:

Jim Garrow, a fringe activist who occasionally appears in far-right media outlets insisting that he is a former intelligence agent out to expose Obama’s plan to speak to aliens, launch a Canadian invasion of the U.S. and kill 300 million Americans, has also promoted the claim, with a twist involving George Soros.

Garrow pointed to a spike in dolphin deaths, which were likely caused by the BP Gulf of Mexico oil spill, as proof that three U.S. military officials thwarted Obama’s plot by detonating a nuclear bomb in the ocean, keeping Charleston safe from attack.

He told Jones that these three patriots, along with God, stopped Obama by safely detonating one of the devices off of the Carolina coast. Garrow’s bizarre claims must have struck a chord, as he appeared last year alongside then-Rep. Kerry Bentivolio, R-Mich., and aspiring anti-Obama coup leader Paul Vallely at a Michigan “Freedom Summit.”