The agreement was aimed at ensuring that Tehran's nuclear program "will be exclusively peaceful" in return for the lifting of sanctions.
European Union High Representative for Foreign Affairs and Security Policy Federica Mogherini, Iranian Foreign Minister Mohammad Javad Zarif, British Foreign Secretary Philip Hammond and Secretary of State John Kerry stand together in July 2015.Carlos Barria / Pool via AFP - Getty Images file
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The agreement was aimed at ensuring that "Iran's nuclear program will be exclusively peaceful." In return, it lifted U.N. Security Council and other sanctions, including in areas covering trade, technology, finance and energy.
The deal was sealed in July 2015, under President Barack Obama.
Critics also allege that the deal itself is flawed and does not prevent Iran from engaging in aggressive actions that fall outside the pact’s purview, such as pursuing a ballistic missile program and expiration dates on some restrictions, as well as extending its influence throughout the region.
President Donald Trump has made no secret of his dislike for the agreement, calling it “the worst deal ever” while on the campaign trail.
On May 8, 2018, Trump announced the U.S. would reimpose sanctions on Iran, leaving other nations involved scrambling to salvage the pact.
Restoring sanctions amounts to a U.S. breach of the original deal whereas Iran was deemed to be compliant, according to international nuclear inspectors.
While the two cases are “very different,” Iran offers lessons to those involved in similar negotiations with North Korea, according to Suzanne DiMaggio, a senior fellow at New America, a Washington think tank where she directs a long-running U.S.-Iran policy dialogue.
“The process of diplomacy that the United States pursued with Iran could offer some insights on how to begin engagement with an adversary whose leadership is extremely distrustful of the United States and vice versa,” she wrote in a post for the Arms Control Association.
Regional U.S. allies, such as Saudi Arabia and Israel, are vehemently against the agreement, saying it has not worked to curb Iran’s aggressiveness or ambitions.
Some of Iran's policies in the Middle East run counter to U.S. interests and those of its allies. Tehran threatens Israel, backs Hezbollah — a powerful Lebanese militia and political group — and is involved in conflicts in Yemen, Iraq and Bahrain.
The Trump White House has also been critical of Iran for its support of President Bashar al-Assad during Syria's seven-year civil war.