First, the Paris accord is almost certain to be a very good deal for us (as I discussed here), and Trump sees himself as a great deal-maker above all else. Second, Trump understands the value of “brand” — and nothing would ruin his brand (or this country’s) more permanently than to be the guy (or country) who killed the world’s best (and maybe only) chance of getting onto a path that could avoid catastrophic warming and centuries of misery for billions of people.
If, as Trump said Sunday, he won’t torch the Iranian nuclear deal, then he isn’t going to burn any Paris accord — and that means he’d have to honor the EPA’s Clean Power Plan, since that is essential to the U.S. side of the deal.
If there were a Paris deal and the United States simply torched it, however, then President Trump and the United States will be blamed for whatever catastrophic climate change subsequently occurs. We would be the ones who ripped the tourniquet off that had stanched the bleeding.
A brand-obsessed deal-maker is not going to invite permanent brand destruction and historical notoriety of the kind enjoyed by leaders like Neville Chamberlain and Herbert Hoover — all to destroy a global deal that requires minimal effort to fulfill.