What are Trump's options for the Iran nuclear deal?

— -- President Trump faces a series of pivotal challenges at the United Nations General Assembly in New York this week, but among the most fraught foreign policy questions for the new president is what he will do with the Iran nuclear accord.

Trump blasted the agreement in his address to the international body Tuesday, calling it “an embarrassment” and “one of the worst and most one-sided transactions the United States has ever entered into.”

“We cannot abide by an agreement if it provides cover for the eventual construction of a nuclear program,” Trump said, warning other world leaders, “I don't think you've heard the last of it.”

Trump must soon decide whether to recertify Iran’s compliance with the deal or set off a chain reaction that could end in the U.S. snapping sanctions back into place and effectively destroying the accord. But as America’s allies continue to support what’s formally known as the Joint Comprehensive Plan of Action, or JCPOA, doing so could force America to once again stand alone on the world stage, with potentially disastrous consequences.

The next deadline

Trump signed waivers on nuclear sanctions against Iran again Thursday, keeping the U.S. in compliance with its end of the agreement that offered Iran relief from crippling international sanctions in exchange for inspections on its nuclear facilities and limits on its nuclear capabilities.

But all eyes are on the next deadline, Oct. 14, when the administration must certify to Congress that Iran is meeting its obligations under the agreement and that the deal remains in line with U.S. national security interests.

That certification is required every 90 days under U.S. law. And although it is not as part of the agreement itself, it is now in jeopardy by Trump’s own admission.

After the last certification in July, Trump told the Wall Street Journal he expected to not do so again the next time, saying, “If it was up to me, I would have had them noncompliant 180 days ago.”

Option 1: Stop signing sanctions waivers

If Trump really wanted to end the deal, he could stop waiving U.S. sanctions on Iran for its nuclear program on his own, which would be a “material” breach of the agreement that would effectively destroy it and allow Iran to walk away. If that happens and the deal unravels, and Iran is able to (depending on who you ask) resume or accelerate its pursuit of a nuclear weapon, the administration would likely face the brunt of the blame.

This is a very unlikely move, sources tell ABC News, especially because it would also be deeply unpopular with U.S. allies and damaging to American credibility.

Option 2: Decertify the deal

Instead, the administration is more likely considering either not certifying the accord next month by claiming Iran has violated its end of the agreement, or vigorously enforcing the agreement as is while continuing to slap Iran with non-nuclear sanctions.

The decertification option was laid out by U.S. Ambassador to the U.N. Nikki Haley in a speech earlier this month. If the administration does that, it punts responsibility to Congress, who would have 60 days to determine whether or not to vote sanctions back into place. The text of bill is already written, laid out in the Iran Nuclear Agreement Review Act, so it would only require a simple majority vote.

There is a secondary step to this option that the administration may be planning as well. Kicking the debate to Congress, some have argued, would also give the administration leverage with Iran –- a shot across the bow that sanctions could be imminent if they do not renegotiate the terms. The U.S. could give Iran 90 days to meet certain new conditions, including opening military sites to international inspectors, according to a memo obtained by Foreign Policy.

But the agreement is not just between the U.S. and Iran. Six other partners –- China, Russia, the U.K., France, Germany, and the European Union -- are all involved and have consistently said the deal is not up for renegotiation.

It’s unclear if threatening the return of U.S. sanctions is enough to leverage either option, especially when other countries who have already begun investing in Iran and would likely not follow suit unless Iran was clearly violating the existing deal.

"You can't achieve 125 percent of this deal with 80 percent -- or 90 percent even -- of the leverage we had before, so you would have to bring other things to the table, not just pressure," Colin Kahl, an adviser to Obama, told reporters Wednesday.

Option 3: Enforce the deal with zeal

The other option -- keeping the deal alive but enforcing it vigorously -- is one the administration seems loath to do, especially after Trump’s comments to the U.N. Tuesday. So far, this is exactly what the White House has done, continuing to uphold America’s obligations by waiving sanctions on Iran while adding non-nuclear sanctions to target Iran’s cyber espionage and sabotage programs, ballistic missile capabilities, human rights abuses, and support for terrorist organizations like Hezbollah.

Supporters of the accord say keeping it alive is crucial because it provides international oversight of Iran’s nuclear programs, a position advocated by Secretary of State Rex Tillerson and other senior administration officials.

If the deal were to fall apart, "Iran would be back on the march to getting the potential for a nuclear weapon and the IAEA would lose all visibility into the program," Wendy Sherman, the lead negotiator of the accord under President Obama, told reporters Wednesday.

Part of this pathway could include adding to the agreement, something the administration is reportedly proposing to European allies, according to Bloomberg, including demanding an extension to limits on Iran’s uranium enrichment which will expire in 2025 and 2030.

But Trump told the U.N. the deal was being used as a cover for the pursuit of a nuclear warhead anyway, and Haley has charged that Iran has been caught in “multiple violations.” To them, the deal is not doing what it was intended to do, and the U.S. shouldn’t be held to it any longer.