Last week, I struck a hopeful note after GOP Sen. Lindsey Graham expressed interest in a climate bill compromise that included a carbon cap in exchange for support for some nuclear power and coastal drilling. But my expectations it would really happen remained low.

Today, Graham made a deal all but inevitable.

Final compromise language is far from complete. But for the conservative South Carolinian to explicitly back “aggressive reductions in our emissions of the carbon gases that cause climate change” (!) in a joint op-ed with Massachusetts liberal Sen. John Kerry (!!) published in pages of New York Times (!!!), Graham has already done all he could to infuriate the conservative movement and many voters in his conservative state.

In other words, Graham has already assumed the political risks for doing a deal. And there’s no point in taking those risks unless you actually do the deal. He has crossed the climate Rubicon.

(Though perhaps he can get away without anyone finding out. Amazingly, Sen. Graham appeared on NBC’s Meet The Press today and failed to get a single question on the landmark op-ed. The long-standing Sunday show aversion to environmental issues remains stupefying.)

Climate Progress’ Joe Romm predicts that Sen. Graham’s support would bring along as many as six other Republican senators. While the Democratic caucus remains split along geographical lines, that level of Republican support would make it extremely likely that 60 senators would at least vote to cut off any filibuster attempts.

(Note that the Senate earlier rejected any possibility of passing climate legislation through Senate budget rules that preclude filibusters. It is truly sixty or Bust.)

Also striking, Sens. Graham and Kerry promote a “border tax” to pressure other exporting nations “that do not accept environmental standards” because “we cannot sacrifice another job to competitors overseas.”

The House climate bill has that provision, but President Obama spoke out against the carbon tariff upon passage, I believe under the presumption the “free”-trade loving Senate would never go for it. Sen. Sherrod Brown earlier stated the opposite was true: a carbon tariff is politically necessary: “I don’t think there’s any way we get to even 50 votes if we don’t deal with manufacturing in the climate change bill … We need some sort of border equalization: temporary, not permanent…”

The Massachusetts and South Carolina senators have clearly reached the same conclusion.

Get Energy Smart Now understandably expresses caution that the devil is always in the details. But Romm enthuses: “I expect the final bill will have no deal-breakers for progressives.” I would think the latter to be true. I said last week, as unpleasant as compromises on nuclear power and coastal drilling may be, they are unlikely to trump the power of a carbon cap.

Romm observes if Senate deal is forged before December’s U.N. climate meeting in Copenhagen, even if the Senate can’t quickly move to a formal vote, the U.S. will have much stronger bargaining leverage to seal an international agreement. With Kerry and Graham in agreement on the basic outlines, reaching such a deal by mid-December looks very plausible.

What was that again, oh wise Washington Establishment purveyors of conventional wisdom, about being unable to handle health care and global warming at the same time?

Originally posted at OurFuture.org.