In his interview  with The Wall Street Journal, Trump all but promises that he won’t approve certifying Iranian compliance with the nuclear deal later this year:
PRESIDENT TRUMP: I think they’ll be noncompliant. I think they’re taking advantage of this country. They’ve taken advantage of a president, named Barack Obama, who didn’t know what the hell he was doing. And I do not expect that they will be compliant.
WSJ: Will you overrule your staff on that, if they come back with a recommendation –
PRESIDENT TRUMP: Oh, sure. Sure. Look, I have a lot of respect for Rex and his people, good relationship. It’s easier to say they comply. It’s a lot easier. But it’s the wrong thing. They don’t comply. And so we’ll see what happens. I mean, we’ll talk about this subject in 90 days. But, yeah, I would be – I would be surprised if they were in compliance.
As I said  a few days ago, Trump seems determined to find a way to renege on the deal. If it means ignoring the evidence that Iran is in compliance with the JCPOA, that is apparently what he’s going to do. Note that Trump just asserts, “They don’t comply,” as if it were a statement of the obvious. He takes that as a given despite the fact that it is plainly untrue. He insists that the other side is “taking advantage” of the U.S. because this is what he says about every international agreement. Trump does not judge any of these agreements by what they actually do, but simply takes for granted that the U.S. is getting ripped off in all of them. He seems incapable of recognizing a good deal when he sees one, and so his judgment of Iran’s compliance with the nuclear deal is bound to be negative no matter what the facts are.
No other party to the agreement thinks Iran isn’t complying with the terms of the deal, and none of the other P5+1 governments will support the U.S. if the administration claims this. Refusing to certify Iran’s compliance will open the door to a new round of U.S. sanctions that Iran hawks in Congress are eager to impose. That would put the U.S. in clear violation of our commitments, and our government will be the one that takes the blame for undermining the deal. Reneging on the deal in this way would tell the world that the U.S. can’t be trusted to honor its commitments. Other governments that might have considered negotiating with us on major issues will have reason to doubt our government when it makes pledges and promises. It could do enormous damage to the effectiveness of U.S. diplomacy in the future. In the worst-case scenario, Iran can use that as a pretext for withdrawing from the deal all together, which will remove the restrictions currently in place on their nuclear program. If that should happen, the danger of a war with Iran increases significantly. Of course, that is what many Iran hawks want, and that is where Trump risks taking the U.S. if he chooses to renege on the deal.