Hostility from Congress and lack of support from the next administration are likely to put the nuclear deal in jeopardy:

Deal skeptics on Capitol Hill have already prepared a raft of bills that have a far better chance of making it into law with the threat of a White House veto now out of the way. But the president-elect himself can just as easily send what he’s called a “disastrous” deal to the dustbin of history by simply refusing to sign off on sanctions relief [bold mine-DL].

“That’s why I find it so hard to believe that the deal survives,” said Richard Nephew, a former State Department sanctions official who now heads the Center on Global Energy Policy at Columbia University. “At some point, [Trump] will have to make an affirmative decision to support its implementation.”

The danger here isn’t just that Trump has repeatedly denounced the deal as one of the worst ever made and has at times vowed to “dismantle” it, but that he also has obvious political incentives to repudiate one of Obama’s signature policies. There was absolutely no Republican support in Congress for the deal, and both chambers are now under Republican control, so it will be easy enough for Trump to satisfy people in his own party and earn goodwill with hawks in Congress by helping to wreck an agreement that he has attacked many times. It would be a serious mistake for him to do this, and it would ensure that his foreign policy record starts off with a huge own-goal for the U.S. that will anger major allies, but I doubt that Trump or the people around him see it that way or care.