CARLOS CURBELO, a Republican congressman from southern Florida, represents a district vulnerable to both climate change and a Democratic swing in the mid-term elections this November. Perhaps that is why, on July 23rd, he offered a bill that would tax carbon pollution. The measure is symbolic and doomed to fail. Just a few days earlier, Mr Curbelo’s fellow Republicans voted overwhelmingly for a resolution calling a carbon tax “detrimental to American families and businesses”. Just six Republicans voted against the proposal. But even that represents progress. When an identical measure was offered in 2016, not one was brave enough to do so.

Republican orthodoxy on climate change can seem unassailable. The party platform pooh-poohs climate change as “far from this nation’s most pressing national security issue” and opposes any carbon tax—generally thought to be the most market-friendly way of reducing emissions. But the odd crack is showing. Some coastal Republicans who must contend with the consequences of a warming planet do not attempt to deny the scientific consensus. Carlos A. Gimenez, the mayor of Miami, was plain when talking about rising sea levels last year: “It’s not a theory. It’s a fact. We live it every day.”

Others have been swayed by political currents. More than half of the Republicans who represent districts won by Hillary Clinton in 2016 are members of the Climate Solutions Caucus, a bipartisan group that advocates climate-change fixes. Some endangered Republicans defend the environment, if only in a NIMBYish way. Unfortunately for the overall sanity of their party, those Republican politicians are the most likely to lose their jobs if a Democratic wave transpires this autumn.

According to a survey by the Pew Research Centre, 52% of Republican voters think there is “solid evidence” of global warming—up from 39% three years ago. Only 24% believe that human activity is to blame, though, compared with 78% of Democratic voters. That huge partisan gap has grown since the 1990s, when President Bill Clinton and Vice-President Al Gore turned green and made it a Democratic cause. “There’s a huge identity-based effect based on the cues Republicans have received from Fox News, conservative media and elected officials telling them that the science is uncertain,” says Matthew Nisbet, who studies political communication at Northeastern University.

Yet moderate and younger Republicans are more likely to agree with the established science. And support for green policies can be found in odd places. Slim majorities of registered Republicans back limiting carbon-dioxide emissions from coal-fired power stations and favour a carbon tax on fossil-fuel companies, according to a survey conducted in March by the Yale Programme on Climate Change Communication. Bob Inglis, formerly a Republican congressman representing South Carolina, who introduced a carbon-tax proposal nine years ago, still thinks it could win support. Conservatives have long had difficulty talking about climate change because the debate is often framed in the “language of repentance, guilt and doing with less, which doesn’t work well in the conservative community”, Mr Inglis says. Carbon taxes are less preachy, especially if they are balanced by tax cuts.

Small signs of compromise can be seen at the edges of climate policy. In February Congress passed a bill that provides tax credits for carbon capture and storage, a technology that prevents emissions from entering the atmosphere by placing them underground. A bipartisan group of senators also pushed through a bill that would speed advanced nuclear reactors to market. Grander schemes are unlikely to succeed during the presidency of Donald Trump, who pulled out of the Paris climate accord. On August 1st he nominated Kelvin Droegemeier, a respected weather expert, as his science adviser. Whether he will follow his advice is a different matter.

The vicious partisanship over climate change is bad for America and the world. That a rich, well-run country cannot pass a bipartisan law to deal with climate change is a tragedy. But if much Republican opposition to climate science is purely political—a way of identifying yourself as not a Democrat—then it can be swayed. Two social psychologists, Leaf Van Boven and David Sherman, have found that Republican voters will back carbon taxes if they are told Republicans favour such a policy. If a leading Republican were to start singing a different tune, admittedly a remote prospect, his or her party could soon join in.

Correction (August 2nd 2018): Matthew Nisbet is a professor at Northeastern University, not at Northwestern University, as previously stated.