It was what happened next that caught my eye: Shortly after Paul’s remarks, a pro-Clinton “rapid response” group called Correct The Record circulated a statement attacking the Kentucky senator. They also emailed me personally to (politely) inquire if I might add it to National Journal’s story.

And they weren’t alone.

Later in the afternoon, the League of Conservation Voters chimed in with a defense of Clinton’s remarks at a green-energy conference Thursday night in Nevada, claiming that Paul’s response “reflects a profound lack of understanding of how serious a threat” climate change poses.

NextGen Climate, the group backed by billionaire green activist Tom Steyer, also went after Paul for his stance on global warming: “A real threat would come from a science-denier as the leader of the free world.”

It remains to be seen whether Clinton will run in 2016—she says she’ll decide early next year. But Friday’s press flurry demonstrates that environmental groups and others on the left are already circling the wagons behind their potential front-runner.