Trump calls the Iran nuclear deal 'the worst' but exiting it could be worse still

A deal is a deal is a deal. Unless it's an Iran nuclear deal.

Try explaining that to Iranian President Hassan Rouhani, who faces the possibility of seeing a three-year negotiation process that resulted in the 2015 Iran nuclear pact crumble at the feet of Donald Trump. This, despite the U.S. president already certifying twice this year that Tehran is fulfilling terms that require it to give up its nuclear weapons program for sanctions relief.

At the United Nationsthis week, Trump hinted the U.S.might pull out of the "embarrassing" six-nation agreement anyway. If it comes to that, Iran experts worry it could make the Islamic republic even more dangerous while eroding trust in the U.S. at the global bargaining table.

"The deal itself is valuable only because it prevents Iran from developing nuclear weapons," said former State Department negotiator Richard Nephew, who helped broker theagreement during the Obama administration.

It may have been an uneasy agreement, but it has worked to keep Iran's finger off the nuclear trigger, said Nephew, now with Columbia University's Center on Global Energy Policy.

Credibility concern

Without a backup plan for slowing Iran's nuclear program, it's not clear what the U.S. stands to gain by withdrawing from the international agreement. What does seem clear, Nephew says, isany goodwill across the U.S.'s international commitments would be compromised.

"We lose credibility. We lose the ability to say, 'Once we make a deal, we stick with it.'"

None of this bodes well should the U.S. try to persuade North Korea to give up its nuclear arsenal, said John Hughes, a former State Department deputy director of economic sanctions. Imperfect as it may be, defenders of the Iran deal still view it as a sign of progress and a potential diplomatic model for Pyongyang to consider.

If North Korea is to even imagine a future non-proliferation agreement, it would need to trust the U.S. to be an honest broker.

"It's one thing if Iran is actually violating the deal," Hughes said. "But to all of a sudden walk away, without justification, [the U.S.] would be questioned by allies as to why they would be a reliable partner to anything. It would do lasting damage if the U.S. is seen as a country that cannot live up to our commitments."

In his UN address, Iranian President Hassan Rouhanidismissed the Trump administration as "rogue newcomers to the world of politics," saying it would be a "pity" for the new commander-in-chief to end a disarmament agreement that "belongs to the international community."

The more than 100-page agreement was reached in July 2015 with the five permanent members of the UN Security Council China, France, Russia, the U.K. andthe U.S. and Germany, along with the European Union.

China and Russia have stated they do not wish to hash out a new accord. Rouhani was unequivocal, telling reporters at the UN: "The nuclear deal cannot be renegotiated."

"It took three years of intense negotiations to come up with that agreement," said Gary Sick, an Iran expert who served on the U.S. National Security Council in the Carter administration. "That deal was intricate. It was complicated. And if the Trump administration wants to go back and redo it, they're going to have to put something on the table, because the Iranians will ask a legitimate question: 'What do we get out of it?'"

Nothing yet, it seems. Pressed on what the U.S. is willing to offer, Trump has not revealed details, only saying he's decidingwhether to scrap the deal.

"I'll let you know what the decision is," he teased reporters at the UN.

What's actually in the deal

Opponents of the deal note that Iran has tested ballistic missiles. Even so, such non-nuclear activity is not prohibited under the deal's terms.

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As much as the White House might object to Iran's ballistic missile tests, as well as its continued support of Hezbollah and the Syrian regime, and its role in destabilizing Yemen, Sick said those criticisms misinterpret what the Iran deal was meant to do.

"Which is to make it virtually impossible to build a nuclear weapon," he said.

"Every single problem [the Trump administration] mentions with regard to Iran and the Middle East would be made instantly worse if you didn't have the nuclear agreement in place."

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The Iran accord mandates regular UN inspections. While it was designed to block Iran from acquiring a nuclear weapon for at least the next decade, it also includes "sunset clauses" for different sanctions that would expire after, say, 15 or 25 years, at which point the country could theoretically race to compile fissile material again.

Trump has called it the "worst deal ever." He's seeking extended deadlines and tougher provisions.

Anthony Ruggiero, a senior fellow and financial sanctions expert with the conservative-leaning Foundation for Defense of Democracies, also wants to see tougher restrictions.

"The Iranians got a sweet deal," he said. "They negotiated a limited nuclear deal, they're receiving benefits for that, while their other problematic activities are not addressed in the deal at all."

But he also stressed the U.S. must be careful not to take responsibilityfor breaking the deal,lest it risk harmingrelationships with its European partners.

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Trump, meanwhile, faces a looming deadline.

Part of the agreement dictates that the U.S. president must "re-certify" every 90 days whetherthe Iranians are in compliance with the terms. Trump re-certified thisin April and again in July. He must do so again on Oct. 15.

Otherwise, the matter goes to Congress, which would have 60 days to vote by simple majority on whether to waive the sanctions again.

If the sanctions are imposed, experts say there's no guaranteeIran would exit the deal. It could continue to live up to its end of the bargain with the remaining five signatory countries and the EU, leading to a scenario in which major European powers would be working with Iran, not the U.S., for the sake of global security.