The writer, a Democrat, represents Rhode Island in the Senate.

Talking to my Senate Republican colleagues about climate change is like talking to prisoners about escaping. The conversations are often private, even furtive. One told me, “Let’s keep talking, but you can’t let my staff know.”

The dirty secret is that climate change is not really a partisan issue in Congress. Its history has not been partisan, with Republican senators such as John McCain, Lamar Alexander, Susan Collins, Lindsey O. Graham and Jeff Flake (as a House member) having introduced climate bills in the past. Climate change became partisan in 2010, shortly after the five Republican-appointed justices of the Supreme Court upended a century of law and precedent to issue the Citizens United decision, which rejected limits on corporate spending on political campaigns. The timing is not a coincidence.

Big-business interests, particularly the fossil-fuel industry, led the charge. That industry’s annual U.S. subsidy is $700 billion, according to the International Monetary Fund. With stakes that high, the incentive to protect the subsidy and the amount that the fossil-fuel industry can afford to spend on political influence are enormous, so the restraints of campaign finance and disclosure rules were particularly galling.

The justices allowed the fossil-fuel industry to roll heavy artillery out onto the political field, not just its previous musketry. Industry operatives brag about putting hundreds of millions of dollars into each federal election cycle, though undisclosed “dark money” and identity-laundering pass-throughs make this increasingly hard to track. Most recklessly, the five justices missed the point — or didn’t care — that anyone who is allowed to spend unlimited political money necessarily can threaten to spend unlimited political money. This atmosphere has quashed any Republican effort on climate change, silenced serious climate debate in Congress and ended progress, as desired and directed by the fossil-fuel industry.

Republicans are not idiots. On the Senate Armed Services Committee, they hear the military warn of climate change as a catalyst of conflict and a threat to low-lying military bases such as Norfolk and Diego Garcia. At their home-state universities, they see climate science in action. Those with coasts see sea levels rising and fisheries going awry; those with forests see pine beetles spreading and wildfires raging; those with farms see unprecedented drought and unprecedented cloudbursts. Republicans hear about climate science from national laboratories and national science and health organizations. They see overwhelming polling numbers showing young voters — even young Republican voters — in favor of climate action.

Republicans are trapped. The merciless might of the fossil-fuel industry’s new post-Citizens United political armaments is directed at them. After I gave a speech about the hoodlum politics of the fossil-fuel industry, a Republican friend approached me on the Senate floor and said: “What the hell are you complaining about? They’re spending more against us than they are against you!” I suspect they were at the time. The fossil-fuel industry knew that if it could bring a political party to heel, it could use that party to block progress.

A climate solution will require safe passage for Republicans through the political kill zone. Democrats can’t help with that. Environmental groups can’t help with that. Scientists can’t help either. It will take the corporate “good guys” to make that happen. Companies such as Walmart, Coca-Cola, Bank of America, Google and General Mills signed the American Business Act on Climate Pledge and do great work inside their fences and sometimes out through their supply chains. But U.S. companies don’t lobby Congress for climate action and have never gathered to tell a Republican senator, “Look, we get what the fossil-fuel guys are threatening you with, but if you vote with us on climate, we will promise to have your back.”

Today, the stakes are higher, and we need reinforcements more than ever. President-elect Donald Trump is filling his administration with the likes of Oklahoma Attorney General Scott Pruitt, an ardent acolyte of the fossil-fuel industry, and ExxonMobil Chief Executive Rex Tillerson. (Take no comfort in Tillerson’s statements that climate change is real and that Exxon supports a carbon tax; that message was never delivered to the fossil-fuel industry’s political gun decks and is a perhaps a deliberate false flag.) Trump may have won the presidency, but the Koch brothers and their fossil-fuel polluter allies are swiftly moving in to run the show. Corporate America can no longer ignore the enforced stagnation on Capitol Hill.

Republicans aren’t cowards. Many will take the side of climate principle in a fair fight. But it is asking a lot of them to take a principled stand on climate when they don’t see one corporate friend ready to help them. That’s the climate battle’s other dirty secret: In Congress, on climate, corporate America is not even trying. That’s why the fossil-fuel bullies own the place.