ATLANTA – Georgia’s former governor has thrown his clout behind the environmental movement to protect the Okefenokee Swamp, a move observers say will have political ramifications even though the legal impacts are probably minimal.

Sonny Perdue, a cabinet member during President Donald Trump’s first term, sent a letter to the U.S. Department of the Interior two weeks ago urging support for a years-long effort to get the national wildlife refuge designated as a United Nations World Heritage Site.

Perdue, who became chancellor of the University System of Georgia after serving as agriculture secretary for Trump, sent the message on Board of Regents letterhead, as reported by The Atlanta Journal-Constitution Wednesday.

The April 17 letter to Interior Secretary Doug Burgum cites a study by an environmental conservation group that said the designation would be an economic boon for the area around the Okefenokee.

“This effort represents an extraordinary opportunity to preserve a national treasure while also delivering incredible economic benefits to the state of Georgia,” Perdue wrote.

The letter did not mention the controversy surrounding one of the world’s largest freshwater ecosystems: draft permits the Georgia Environmental Protection Division has given to Alabama-based Twin Pines Minerals for a titanium mine along the southeastern border of the swamp.

The company has said the project would not damage the refuge, but opponents cite research showing it would threaten water levels, increase the risk of wildfires, harm wildlife and pollute the water with toxins.

Twin Pines President Steve Ingle said in response to Perdue’s letter that World Heritage designation by the United Nations Educational, Scientific and Cultural Organization would not affect the company’s bid for a mining permit.

“The application for World Heritage designation does not have any bearing on our permit application, nor does it impact our plans to mine for titanium and zirconium in Charlton County,” Ingle said in a statement issued through a spokesman. He said the company’s “exhaustive, comprehensive” studies show that the proposed operations nearly three miles from the refuge would not harm the Okefenokee “or surrounding environs.”

But mine opponents said Perdue’s letter carries political weight that could influence the state’s permitting decision, as Trump considers rolling back conservation on public lands.

“Sonny is basically putting his imprimatur, for whatever it’s worth, on a very popular issue in his home state and he’s putting it into a global context,” said veteran Georgia environmental lobbyist Neill Herring. “And he’s basically telling the president, ‘Don’t go there.’ “

Perdue’s letter comes after fellow Republican U.S. Rep. Buddy Carter of Savannah joined Democratic members of the state’s congressional delegation in sending a similar letter to the Interior Department in February.

Josh Marks, President of Georgians for the Okefenokee, which opposes the mining permits, praised Perdue’s stance and said he hoped it would influence the administration of Gov. Brian Kemp.

“It’s time for Governor Kemp to stand up for the Okefenokee by saying no to mining and yes to World Heritage Site listing,” he said, adding that a mine could jeopardize World Heritage designation “because external threats are a key factor in the evaluation process, and the scientific community universally says mining will damage the swamp.”