In one of the futile demonstrations that marked the run-up to the Iraq war, I saw a woman with a sign that read “How Did Our Oil End Up Under Their Sand?” In nine words she managed to sum up a great deal of American foreign policy, back at least as far as the 1953 coup that overthrew Mossadegh in Iran and helped toss the Middle East into its still-boiling cauldron.

If the Senate approves Rex Tillerson after his testimony on Wednesday, they’ll be continuing in that inglorious tradition – in fact, they’ll be taking it to a new height, and cutting out the diplomats who have traditionally played the middleman role.

Rex Tillerson – who has literally spent his entire working life at Exxon – is big oil personified. It’s like appointing Ronald McDonald to run the agriculture department (which is certainly a possibility, since that job is still unfilled).

All in all, it’s hard to imagine a single hire that could do more damage to the planet

So in one sense Tillerson’s appointment simply makes formal what has long been clear. But in another way, his announcement is truly novel: the honor (secretaries of state are usually considered the second-most important official in our government) comes after a season of disgrace at the world’s largest oil company, in a moment when the energy business is on the ropes and when its product is causing the greatest crisis the planet has yet faced.

Those three things are linked, of course. The disgrace is the long, slow reveal by investigative reporters that Exxon knew all about climate change as early as the late 1970s. Their scientists were so far ahead of the curve that management was taking precautions and planning strategy a quarter-century ago – building drilling rigs to account for the sea level rise they knew was coming, and plotting to bid for leases in an Arctic they knew would melt.

But instead of telling the rest of us, the investigations revealed their deep involvement in the effort to spread doubt and confusion about climate change. Given the consequences, this is a series of corporate crimes that makes VW’s emissions cheating seem like stealing a candy bar from the 7/11. In a rational world, Congress would be grilling Tillerson about the company’s conduct, not preparing to hand him the country’s plum unelected job.

Exxon knew of climate change in 1981, email says – but it funded deniers for 27 more years Read more

But climate change means not just the collapse of the planet’s fundamental systems (after the hottest year ever measured, global sea ice has been charting record lows – literally the world looks different from outer space). It also means that the energy business is in serious trouble.

Big oil has underperformed on the stock market for years. Exxon’s once-sterling profit record is now checkered at best. And as a result it’s resorted to every kind of chicanery. USA Today reported on Monday that, through a European subsidiary, it managed to do business with Iran, Syria and Sudan while those countries were under US sanctions (sanctions the, um, secretary of state would need to enforce). Everyone knows that the company stands to make billions-with-a-B if America lifts its sanctions on Russia. With its business in decline, these are the kinds of moves that Exxon has been reduced to plotting.

The global response to climate change is the third part of the puzzle. If we listened to climate scientists and ramped up our commitment to change, the oil business would suffer deeper damage yet. That was the hope of the Paris accords, which called for ratcheting up the modest plans agreed to in 2015, in accordance with emerging science.

But now the guy responsible for our participation in the Paris process will be able to make sure that doesn’t happen. He can’t save Exxon and its kin long-term – the rapidly falling price of renewables will see to that – but he can keep it from being pinched harder over the next few years, even at the cost of pushing the planet’s carbon load past every benchmark the scientists have warned us against.

All in all, it’s hard to imagine a single hire that could do more damage to the planet (though the rest of Trump’s cabinet will doubtless give him a run for his money). Making this man secretary of state rewards climate denial, further warps our foreign policy towards oil and does it at the precise moment when every bit of data screams that we should be going in the opposite direction.

The only consolation is that it removes all the window-dressing. Big Oil will run our foreign policy, right out in the open. In that sense, I suppose, Trump gets credit for a kind of barbaric transparency. When the CIA overthrew Mossadegh at least they had a little shame about it. No more.