Donald Trump has said it repeatedly, both during the campaign and in the first nine months of his presidency: the 2015 agreement between Iran, the United States, the European Union and members of the U.N. Security Council to rein in Tehran’s nuclear weapons program, “is the worst deal ever.”

Soon enough, we’ll know if Trump means what he says. The deadline for recertifying the deal is October 15, and the White House has already completed a review of U.S.-Iran policy, led by National Security Adviser H.R. McMaster. An administration source, who, like others interviewed for this piece, was not authorized to speak on the record, says it likely will be announced before the deadline.

What will Trump’s decision be? Two sources involved in the Iran policy review say that despite Trump’s recent assertion that he’s already made up his mind, the administration is still mulling its options. Trump wants out of the accord, which also involved ending sanctions against Tehran. But the president has also come to understand there would be a serious diplomatic fallout if he simply scraps the agreement. All other signatories, including America’s closest European allies, do not want Washington to blow up the deal. They, like the International Atomic Energy Agency, believe Iran has mostly abided by its terms, and since the sanctions ended, have begun doing business with Tehran again. They’ve also been lobbying the administration to stay in the agreement.

Related: Why the Iran nuclear deal is at risk of unraveling

Meanwhile, Secretary of State Rex Tillerson has been lobbying the Europeans, trying to persuade them to join with Washington in pressuring Iran to improve the terms of the deal. And he’s had some success. French President Emmanuel Macron—with whom Trump has a good relationship—has said he was willing to address the so-called “sunset provisions” in the accord, which effectively allow Tehran to have a full nuclear program in 15 years. He agrees with Washington that the U.S. and its allies need to push back harder against Iran’s increasing influence in the region, and in particular, the regime’s support of Syrian strongman Bashar al-Assad. But he insists that Trump and company shouldn’t scrap the agreement.

Sources involved with the Iran review say one option that has gotten serious consideration by the president and his advisers is to “decertify” the deal. That is, to say that he doesn’t believe Iran is abiding by its terms, but to remain in it. Pulling out of the agreement entirely would require reimposing sanctions on Tehran. The president, on September 14, has already said doing that would not be in the U.S.’s “national security interest.” But many GOP members of Congress have been itching to restore these sanctions. Trump, however, could tell them to hold off—and it’s virtually certain that they would.

Arkansas Senator Tom Cotton, an uber-hawk on Iran and a steadfast critic of the deal, has said he’s fine with that option as long as the administration forces Iran to renegotiate the deal. Cotton’s approval was a sign, an administration official said, that this option would have strong support among Republicans on the hill: “No one gets to the right of Tom Cotton on Iran.”

Yet staying within the agreement’s framework while publicly saying Iran is not abiding by its terms carries big risks. It effectively means the administration is asking for a do-over with Tehran. Iran hawks have a wishlist of things they’d like to see in a new agreement. The president, says Mark Dubowitz, chief executive officer of the Foundation for the Defense of Democracies, a foreign policy think tank, “should insist on conditions making permanent the current restrictions on Iran’s nuclear program and the testing of advanced centrifuges and nuclear-capable ballistic missiles (those restrictions now phase out over time), as well as the buying and transferring of conventional weaponry.” He should also, Dubowitz says, “insist on unfettered access for U.N. weapons inspectors to Iranian military sites,” where the U.S. suspects nuclear research occurred and may still be occurring.

The Europeans have been privately telling Washington that Iran won’t accede to such demands. Making them, they fear, may prompt the country to walk away from the agreement entirely and push toward a nuclear breakout. That, potentially, could hand Washington a second nuclear crisis at a time when it is desperately trying to deal with the first one in North Korea. Asked if the White House has the bandwidth to deal with that, an administration official said simply, “I don’t know. It's a reasonable question.”

McMaster and Defense Secretary James Mattis are not fans of the Iran deal, or the leadership in Tehran. From their experience in Iraq, they know how many U.S. servicemen were killed by Iranian weapons or Tehran-backed Shiite militias during the war. They’ve also seen, in places like Syria and Yemen, Iran’s malign influence in the region spread since the accord. Their counsel to the president—which has not leaked to date—will be important in shaping Trump’s decision. Iran hawks say that while Tehran will make a huge fuss publicly if Trump decertifies the agreement, the prospect of renewed sanctions would ultimately bring them back to the table for round two of negotiations.  

We may soon find out if they are right.