Saturday, May 12, President Donald Trump will announce the most significant decision of his first sixteen months in office. Either he will withdraw from the agreement that stopped Iran’s nuclear advance in 2015, or alternatively, he will maintain what he believes is a “bad deal” while demanding that it be strengthened. As he has noted, this decision will not only impact America’s security but even more directly and immediately the security of our ally, Israel. As he considers this fateful choice, the president should ask less “what does Bibi think?” And more “what do Israeli security professionals advise?”

President Trump is expected to announce today or tomorrow that he is taking the first step to bury the Iran nuclear deal. That 2015 agreement pushed Iran’s nuclear program back from a few months away from a bomb to over a year. By “decertifying” the deal, Trump will hand the ball to Congress, inviting it to reimpose sanctions on Iran. That would mean, in effect, unilateral American withdrawal from the agreement, freeing Iran from its current constraints and allowing it to resume its quest for a bomb.

The attacks in Brussels last month were a stark reminder of the terrorists’ resolve, and of our continued vulnerabilities, including in an area of paramount concern: nuclear security.

The attackers struck an airport and the subway, but some Belgian investigators believe they seemed to have fallen back on those targets because they felt the authorities closing in on them, and that their original plan may have been to strike a nuclear plant. A few months ago, during a raid in the apartment of a suspect linked to the November attacks in Paris, investigators found surveillance footage of a senior Belgian nuclear official. Belgian police are said to have connected two of the Brussels terrorists to that footage.

The nuclear issue has dominated relations between the US and Iran over the past decade. Now that the two countries have shelved that issue by agreeing to the Joint Comprehensive Plan of Action, it is appropriate to ask where and how the national interests of both countries converge and conflict.

Six months after the United States Senate failed to block the Iranian nuclear agreement, the Islamic Republic has taken major steps to dismantle its nuclear infrastructure. The International Atomic Energy Agency (IAEA), which is monitoring the country’s compliance, declared that Iran has fulfilled its initial nuclear commitments, and most international sanctions on Iran have been lifted.

Graham Allison, Director of the Belfer Center for Science and International Affairs, Joseph Nye, Harvard University Distinguished Service Professor, and James Walsh, Research Associate with the Security Studies Program at MIT were among a group of 53 national security leaders and analysts who signed a statement supporting the implementation of the Iran nuclear agreement. The statement highlights the progress made by the agreement in limiting Iran's nuclear program and reaffirms, despite continued differences between the United States and Iran, the value of diplomacy in resolving international disputes.

The Iran nuclear deal was officially implemented on Saturday, as Iran successfully fulfilled its initial key nuclear commitments and the international community relieved major sanctions, including unfreezing about $100 billion of Iranian money. Implementation Day was met with applause from deal supporters in the U.S. and Iran, while critics have raised questions about whether Iran will adhere to its requirements and how it will flex its newfound economic power. Also in recent days, the U.S. and Iran agreed to a prisoner swap that led to the freedom of Washington Post reporter Jason Rezaian and others, and negotiated the release of American sailors detained in Iran. What does the arrival of Implementation Day mean for Iran’s nuclear program and nuclear nonproliferation, and how does it bode for the future of U.S.-Iran relations? We asked Belfer Center experts to weigh in on these and related questions.

The International Atomic Energy Agency released its “final assessment” yesterday of the possible military dimensions of Iran’s nuclear program.