President Trump is weighing whether to nullify the Iran nuclear deal next month, as proponents of the agreement rally to its defense ahead of a key deadline that will force Trump to reevaluate its future.

The president faces pressure to fulfill his campaign promise to end the Iran nuclear agreement, which he has called the "worst deal ever negotiated." Known formally as the Joint Comprehensive Plan of Action, the deal requires the State Department to certify to Congress every 90 days that Iran is still complying with the agreement under the terms ironed out by the Obama administration in 2015.

Some top Trump aides have urged the president to preserve the Iran deal at the next 90-day mark in October. H.R. McMaster, his national security adviser, and Secretary of State Rex Tillerson have cautioned Trump against scrapping the JCPOA despite his deep skepticism of the agreement, a source familiar with the talks told the Washington Examiner.

But others close to the president have urged him to follow through on his threats to dismantle the deal and have attempted to craft a new strategy for dealing with Iran in the event Trump ends the JCPOA.

Sebastian Gorka, former strategist to the president, said Trump resisted the recertification process at the most recent 90-day deadline in July, when he requested more information from his aides about how he could end the agreement.

"The president didn't want it recertified last time," Gorka told the Washington Examiner.

The former White House adviser, who stepped down last month, suggested Trump did not undo the Iran deal this summer only because he had not yet received from his team a set of satisfying alternatives to the agreement.

"Last time, he didn't do it because he hadn't been given an adequate path, the scenario hadn't been provided to him" to decertify the deal, Gorka said.

But soon after Trump requested a draft plan to dismantle the Iran deal, Gorka said he and another top aide tasked with overseeing the creation of the plan, former White House chief strategist Steve Bannon left the West Wing and were unable to pass on their findings to the president.

"Those options were never presented to him because of Steve's resignation and my resignation," Gorka said.

Bannon had enlisted the help of at least one outside adviser to give Trump options should he choose to exit the Iran deal.

John Bolton, former U.S. ambassador to the United Nations, wrote in a late August memo published in National Review that Bannon had approached him shortly after the most recent recertification and asked him to prepare a "game plan" for withdrawing from the JCPOA.

"[S]taff changes at the White House have made presenting it to President Trump impossible," Bolton wrote of his Iran deal withdrawal plan. "Although he was once kind enough to tell me ‘come in and see me any time,' those days are now over."

Bolton's memo advises Trump to conduct "early, quiet consultations," beginning with private phone calls from the president, with key allies like Israel and countries that had signed onto the deal, such as France and Germany. Those early conversations should provide a friendly warning about the decision ahead and should help those countries understand why the administration was pulling back from the agreement, Bolton wrote. Then, Bolton advised Trump to undergo an expanded diplomatic campaign aimed at rallying support around the world for new sanctions against Iran once the deal was no longer in place.

Proponents of the JCPOA argue the independent inspections Iran must undergo as a condition of the deal have so far turned up no evidence of explicit violations, proving it has been a success. The International Atomic Energy Agency, the organization that perform the inspections, reportedly conducted more than 400 site visits in 2016 and has informed the international community that Tehran remains in compliance with limits on its centrifuges and uranium enrichment.

The Trump administration has publicly given little indication of where the president plans to go with the JCPOA in the coming weeks. Trump has already recertified the deal twice, although in April, he called for a sweeping review of whether the sanctions relief Iran won as part of the deal remains in the U.S. national interest.

"We're continuing to conduct a full review of our Iran policy. That has certainly not changed," State Department spokeswoman Heather Nauert told reporters on Sept. 12. "During the course of the review — and I'll say this again — that we will continue to hold Iran accountable for its malign activities."

U.S. Ambassador to the United Nations Nikki Haley began earlier this month to make the administration's case for breaking with the deal. Instead of focusing only on whether Iran remains within the parameters of the JCPOA, Haley argued, the U.S. should take a broader view of all Iranian provocations, including the activity of the Iranian Revolutionary Guard Corps, support for Hezbollah, and ballistic missile development, and decide on a more comprehensive Iran policy.

"The question of Iranian compliance is not as straightforward as many people believe," Haley said during a speech to the American Enterprise Institute on Sept. 5. "It's not just about the technical terms of the nuclear agreement. It requires a much more thorough look."

The administration moved quickly to signal its low tolerance for Iranian aggression after Trump took office. By early February, Trump had sanctioned more than two dozen people and groups in response to a ballistic missile test Tehran conducted in late January, and his then-national security adviser, Gen. Mike Flynn, had announced that Trump planned to put Iran "on notice" over its provocations.

Trump's State Department reissued waivers in May that continued to lift sanctions on Iran, which the Obama administration had granted in exchange for compliance with the JCPOA. But Trump also hit several Iranian individuals and entities in May with fresh sanctions related to their aggression outside the terms of the nuclear deal.

And the Trump administration issued a new round of sanctions in July aimed at IRGC-affiliated groups that had engaged in ballistic missile development, among other provocative activities.

Fred Fleitz, senior vice president for policy at the Center for Security Policy, said some critics of the deal have presented options that would keep the JCPOA in place while punishing Iran more severely for bad behavior outside of it.

"They're trying to find a way to allow the president to do something so he can make a big announcement without pulling out," Fleitz said of that camp, noting their overall objection for the recertification next month would be to "wrap this in a big, new, anti-Iran policy."

"The jury is out on what the president is going to do," Fleitz said.

But Trump has spent months excoriating the deal and blasting the Iranian regime for its aggression. Fleitz said it would make little sense for Trump to continue approving an agreement he has described as dangerous.

"I just think it's ridiculous to say the deal's not in our interest and stay in it," Fleitz said.

Any effort to abrogate the JCPOA would face fierce opposition from the Iran deal's supporters, all of whom characterize the agreement as the only thing standing between the regime and a nuclear weapon.

However, Trump would earn applause from some members of Congress for following through on his threats to Iran.

Republican lawmakers — including Sens. David Perdue, Tom Cotton, Ted Cruz, and Marco Rubio — have urged Trump to reconsider the suspension of sanctions at the heart of the Iran deal.

Less than a month before the next recertification deadline, one source close to the administration told the Washington Examiner that Trump is "leaning towards decertifying" the Iran deal.

The October benchmark will be the first recertification to occur without Bannon and Gorka, two strong opponents of the JCPOA, on the president's team.

Gorka said he was unsure if anybody left in the West Wing is pushing for a full decertification of the Iran deal. But he noted Trump will ultimately make his own decision, regardless of their counsel.

"I think the president is an army of one," Gorka said. "My prediction is the president will not want to recertify."