For instance, when Hunt-Martorano and her colleagues first met their representative, Lee Zeldin, a Republican, they expressed appreciation for his service in Iraq and in the State Senate before mentioning anything about climate change. “He interrupted us,” recalled Hunt-Martorano. “He said: ‘I just have to say, you guys are not normal. You’re smiling, you’re saying nice things about me. That’s not what people like you do when you come into my office.’ ”

Since then, the volunteers have met with Zeldin or members of his staff 32 times. They understand his interests and passions, and have helped him advance some of his legislative goals. And he became the fifth Republican to join the caucus.

“The Citizens’ Climate Lobby is an exceptional group that is pursuing an amazingly productive, substantive way to engage with members of Congress on both sides of the aisle,” Zeldin told me. “Countless times I’ve had people come into my office to engage on an issue and even if we were on the same page they would be starting off the meeting very aggressive and hostile, and it was counterproductive,” he said.

“The way that we communicate about the issues to achieve clean air and clean water should be bringing our country together regardless of party registration or ideology,” he added. “This really is an issue that everyone agrees on more than anyone’s admitting. There’s a communication gap that needs to be overcome.”

Steve Valk, the group’s communication’s director, put it this way: “If you can let go of being right, you can make a difference.”

When Moyer first began engaging with Love on the climate issue, it didn’t look promising. “She was viewed as a lost cause,” he said. “Everything she said and showed on her campaign website was as friendly to the fossil fuel industry as you can imagine.”

Still, he went to a meet-the-candidates night and asked Love about climate change, and found her to be a terrific listener. Then, on a family trip to Washington, he made an appointment to talk with her environmental aide, who told Moyer that Love needed to hear from other Republicans and her constituents. So he and other volunteers helped set up the conversations and organized a town hall in her district. “We had enough of a track record that she knew we weren’t going to set her up” by packing the hall with belligerent protesters, Moyer said.