WASHINGTON ― Tuesday afternoon, former Vice President Al Gore will join Democratic presidential nominee Hillary Clinton on stage in Miami. They will be greeted by thousands of supporters. Gore is expected to speak about climate change, a topic that has consumed him since leaving office, and the importance of keeping a Democrat in the White House.

But for Gore the moment might be a little bittersweet. He will be returning to a state whose ballot problems and vote-counting politics cost him the presidency in his run against Republican George W. Bush in 2000. The Clinton campaign hopes that by resurfacing memories of that moment, it might remind voters about the perils of backing a third-party candidate. There may never have been the need for a recount in 2000 had some progressives in Florida not voted for Green Party candidate Ralph Nader.

Earlier this year, we interviewed Ron Klain, who helped run Gore’s recount fight. Sitting down with our podcast Candidate Confessional, Klain described all the ups and downs: the long nights, bitter courtroom battles and consequential political decisions. He said he still hasn’t gotten over the loss.

“It was just a horrible, horrible thing,” Klain told us. “I probably think about it several times a week, still.”

Klain said the recount will occasionally come up in his conversations with Gore. But Klain gives credit to the former vice president for his ability to bounce back and devote himself to environmental causes. In 2007, Gore won the Nobel Peace Prize for his work on climate change.

“Vice President Gore, who could have been just unbelievably devastated by this, has gone to build one of the most impressive civic careers of any human fighting for climate change,” Klain said.

Listen to the Candidate Confessional episode: