NCG notes that the Iran deal-formally known as the the Joint Comprehensive Plan of Action (JCPOA)-was a "groundbreaking diplomatic agreement [which] provided the means for Iran to demonstrate that its nuclear activities were permanently and verifiably peaceful".
Political observers have warned that any unilateral action by the United States based on unsupported claims of Iranian non-compliance would isolate Washington, impede future efforts for other nonproliferation agreements in the broader global community and increase the likelihood of a wider conflict in the Middle East.
Under the 2015 deal, Tehran agreed to roll back its nuclear program in exchange for relief from wide-ranging oil, trade and financial sanctions that had choked the Iranian economy. There was always the chance he could still have a last-minute change of heart and certify Iran's compliance with the 2015 accord, which he has called an "embarrassment" and the "worst deal ever negotiated".
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. The agreement has been beneficial for Iran's economy, opening it to foreign markets and the global financial system, said Ahmad Khalid Majidyar, who previously taught Middle East issues to USA and North Atlantic Treaty Organisation military leaders at the Naval Postgraduate School's Leader Development and Education for Sustained Peace program.
Mogherini pointed to other worldwide agreements that the United States has abandoned but the rest of the world has remained committed to, including the Paris Agreement on climate change.
Trump is also expected to seek amendments in the existing deal with respect to the requirement for the USA president to re-certify Iran's compliance every 90 days. The administration also wants to impose penalties or limits for Iran's ballistic missile program and create a stronger enforcement mechanism for potential breaches of the deal.
If, as expected, Trump "decertifies" the nuclear agreement this week, Congress will then have 60 days to decide whether to reimpose sanctions on Iran. "We may have to array our forces to prepare for. calibrated strikes".More news: "It's a possibility" - Dani Alves speaks about Arsenal's Sanchez joining PSG
Drafts of two proposals seen by The Associated Press, one from Senate Foreign Relations Committee chairman Bob Corker and one from committee member and harsh deal critic Senator Tom Cotton, would expand the United States certification criteria to include items that are also the province of the UN nuclear watchdog and require the USA intelligence community to determine if Iran is carrying out illicit activity in facilities to which the International Atomic Energy Agency does not have access. She said, "It is not a deal you can easily open and renegotiate".
Watch Federica Mogherini's full interview with the NewsHour's Judy Woodruff on Wednesday.
What happens if Trump decertifies the deal?
First, Congress could vote to snap sanctions back into place, or Trump could refuse to sign the next round of waivers for sanctions.
Why does U.S. President Donald Trump want to scrap it?
House Democrats met earlier in the day with former secretary of state John Kerry and former energy secretary Ernest Moniz, who were the primary negotiators of the deal made between Iran and six world powers.
The Europeans seem more inclined to try to "build" on the deal in this way.
What exactly that will look like is still being determined, but it could include greater congressional oversight.