On Tuesday night, a Democratic climate advocate ran against a Republican “climate advocate” in Illinois’ 6th district. The results of that race make one thing clear: If conservative politicians want to incorporate the environment into their platforms, they have to mean it. Let’s back up for a second.

In 2016, a bipartisan effort to address rising temperatures formed. The Climate Solutions Caucus said it would “explore policy options that address the impacts, causes, and challenges of our changing climate.” But after the group failed to accomplish, well, anything, the Climate Solutions Caucus appeared to chiefly be exploring one thing: how to shield conservatives running in states where environmental issues matter to voters.

The question leading into the midterms was whether belonging to the caucus would have any impact for Republicans running for reelection. That brings us back to Illinois’ 6th district, where Sean Casten — a Democrat with a background in renewable energy (and a background as a contributing writer to Grist) — beat out six-term incumbent Peter Roskam.

Roskam became a member of the Climate Solutions Caucus in May, two months after Casten won the Democratic primary on a platform that featured climate action front and center. After joining the group, Roskam, alongside a lion’s share of the Republicans in the caucus, voted for a resolution condemning the very notion of a carbon tax. (Putting a price on carbon is a Republican-friendly, market-based approach to fighting climate change, but never mind that.)

Grist thanks its sponsors. Become one.

Roskam’s lifetime score from the League of Conservation Voters — an organization that keeps tabs on how members of Congress vote on green issues — wasn’t anything to write home about. He earned a 7 percent lifetime score from the group, and scored just 3 percent last year. He’s also on record calling global warming “junk science.”

“The Climate Solutions Caucus — I truly don’t know what its purpose is,” Casten tells Grist. “It’s a great way to provide cover for Republicans who want to appear to care, but it’s not lost on anybody in this district that Roskam called climate change junk science and joined the Climate Solutions Caucus right after I won the primary to try to give himself some cover.”

Casten, on the other hand, was unequivocal about his stance on green issues. He called global warming “the single biggest existential threat we face as a species,” and has a plan for what he wants to do about it once he gets to Congress.

As a former CEO of renewable energy companies, Casten says he’s equipped to frame the debate in a way that appeals to both businesses and consumers. “There’s no fundamental conflict between the economy and the environment, provided you focus on efficiency and conservation,” Casten says. He wants to streamline parts of the Clean Air Act to encourage innovation and efficiency. “The Clean Air Act is awesome,” he says. “But it’s got these flaws because it was written in a way that never contemplated regulating CO2.” That’s one of the things he plans to push for in 2019.

Grist thanks its sponsors. Become one.

One thing he doesn’t plan on doing when he gets to Capitol Hill? Joining the Climate Solutions Caucus. “It’s not high on my list of things to do, because it’s really important for me to do something about climate,” he says. “I don’t need any resume bonafides.”

By the time results had rolled in from purple districts across the country on Tuesday night, it became evident that Roskam wasn’t the only climate caucus Republican whose diluted environmental message failed to resonate with voters. In all, 12 other conservative members of the caucus lost their seats to folks with better climate bonafides.

Reader support helps sustain our work. Donate today to keep our climate news free.