In February, he tweeted that Iran "has been formally PUT ON NOTICE," while also grousing about the "terrible deal" his predecessor made. The administration certified that Iran was complying with the deal on July 17, when it was legally required to review the deal, but all accounts from inside the White House suggest that Trump did so extremely reluctantly. This recertification only lasts 90 days, however, so Trump will need to renew it in October. And it seems like there's a real chance the deal doesn't survive that round of scrutiny.
"They are not in compliance with the agreement and they certainly are not in the spirit of the agreement in compliance," Trump said in an August presser. "I think you'll see some very strong things taking place if they don't get themselves in compliance."
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All of this raises a pair of questions: Is Trump making a valid argument when he says Iran is breaking the deal? And if not, what's his actual problems with the agreement?
The answer to the first question is pretty clearly no. The International Atomic Energy Agency, which is in charge of monitoring the deal, has repeatedly certified that Tehran is complying with the limits on its nuclear program. The Trump administration has yet to produce any evidence to the contrary.
It seems instead that Trump's case against the deal is more political and strategic: His team believes that Iran is an enemy of the United States, one that frustrates US objectives in places like Iraq and Yemen, and that the nuclear deal hasn't done much to solve the problem.
"Iran is an adversarial power that is working against the vital interests of the region. The deal doesn't make Iran any better, so the deal doesn't serve our interests," James Jay Carafano, a foreign policy expert at the conservative Heritage Foundation who served on the Trump transition team, tells me.
There's a core truth to this case: Iran's behavior is extremely problematic in a whole host of ways, from testing ballistic missiles to funding violent militia groups around the Middle East.
There are a two big problems Trump's argument, though. First, Iran's support for terror and missile testing — while problematic — aren't prohibited by the deal, so Tehran isn't violating the pact by doing so.
Second, and perhaps more important, there's little reason to believe that scrapping the Iran deal would help the US counter Iran in other areas. The US would have a hard time persuading partner nations to reimpose sanctions if the Trump administration quit the deal for no good reason, which would mean Iran wouldn't suffer very much from an American pullout and thus would have no reason to stop its misbehavior. What's more, it would be completely free to restart its nuclear program.
There is, in short, no good reason to believe that withdrawing from the deal would help solve Trump's real problem with Iran.
"It's just the worst of all possible worlds: You walk away from the deal but you're not going to get the reimposition of sanctions," Jeffrey Lewis, a nonproliferation expert at the Middlebury Institute of International Studies, says. "If this administration walks away from the Iran deal, my suspicion is that Iran will end up looking just like North Korea, right down to the thermonuclear-armed intercontinental ballistic missiles."