The agreement contains specific restrictions on Iran's nuclear program that will expire after predetermined periods of time.
Ahead, we break down the implications of that decision and what could come next. Many will not even discuss what congressional debate might follow if Trump decertifies, instead focusing the arguments for certification.
Since the nuclear deal - formally known as the Joint Comprehensive Plan of Action - took effect in January 2016, Iran has allowed inspections and is seeing some economic payoff.
House Foreign Affairs Committee Chairman Ed Royce, R-Calif., who held a hearing on Iranian threats on Wednesday, called the deal a failed "gamble" that Iran would become a responsible actor. In a recent review of Iran's compliance of the deal, the White House found the country to have met the requirements, yet Trump insisted on scrapping the deal, stating it was no longer in the US' security interests. The law was meant to give Congress an oversight role over the nuclear deal.
Recently Tehran and other signatories to the JCPOA, the five permanent member countries of United Nations Security Council and Germany have joined voices in support of the landmark deal and warned Washington against repercussions of walking way form the multilateral deal.More news: Gordon Strachan blames genetics after missing out on World Cup play-offs
Since taking office, the Trump administration has also signed multiple waivers for nuclear sanctions against Iran.
Mr. Trump has until Sunday to decide whether to recertify that Iran is in compliance with the Obama-era nuclear agreement, which limits Iran's nuclear program.
While the president is required to certify the deal every 90 days, that certification is not part of the deal. He called Trump's move to kick the deal to Congress a "trap" and "a tactic meant to reach the president's goal of tearing the deal apart".
It is also expected that the Trump administration could announce a fresh set of sanctions, possibly non-nuclear, against the Middle East nation like penalties against Iran's ballistic missile programme. North Korea's leaders, meanwhile, would have little incentive to negotiate a nuclear disarmament if they see the Iran deal collapse, he said.
And if that fails, Cotton said, "We may have to impose new, even more coercive, sanctions". "Once it was entered into, once it was implemented, we want to see it enforced. There is [neither] technical, nor political space to renegotiate this deal". French President Emmanuel Macron has expressed concern about Iran's ballistic missiles and the "sunset" provisions as well.
What is the Iran nuclear deal?More news: PH growth forecasts revised by IMF, AMRO
Watch Federica Mogherini's full interview with the NewsHour's Judy Woodruff on Wednesday. If those sanctions are put back into place, the JCPOA would be considered breached. But again, none of that is likely since the USA would be essentially tearing up the agreement and taking the blame for whatever comes next.
"Iran is kind of a long-term destabilizing actor in the region and so we remain concerned about their activities as well", U.S. General Joseph Votel told reporters.
The president has called the Obama administration agreement the worst deal ever.
Iran has already threatened the United States with dire consequences if it imposes sanctions against the country.
The Europeans seem more inclined to try to "build" on the deal in this way. Representative Ed Royce, Republican chairman of the House Foreign Affairs Committee, said the Trump administration should preserve the deal to protect U.S. national security, even though he opposed the deal at the time.
But it could be hard to get both Iran and its ally, Russia, back to the table for a new round of talks.More news: Irving Oil Says Decision to Cancel Energy East Is a Lost Opportunity
Leading House Republicans huddled with national security adviser H.R. McMaster Wednesday evening for a classified briefing on the administration's plan for the 2015 agreement. Many Democrats believe that is more likely to happen if Congress does not act to make changes to the existing agreement.