evidence: Proponents of the deal said that it would help prevent a revival of Iran’s nuclear weapons program and thereby reduce the prospects for conflict between Iran and its regional rivals, including Israel and Saudi Arabia. However, the deal has been in jeopardy since President Donald Trump withdrew the United States from it in 2018. In retaliation for the U.S. departure and for deadly attacks on prominent Iranians in 2020, including one by the United States, Iran has resumed its nuclear activities. UN inspectors reported in early 2023 that Iran had enriched trace amounts of uranium to nearly weapons-grade levels, sparking international alarm. [...] In response to the other parties’ actions, which Tehran claimed amounted to breaches of the deal, Iran started exceeding agreed-upon limits to its stockpile of low-enriched uranium in 2019, and began enriching uranium to higher concentrations (though still far short of the purity required for weapons). It also began developing new centrifuges to accelerate uranium enrichment; resuming heavy water production at its Arak facility; and enriching uranium [PDF] at Fordow, which rendered the isotopes produced there unusable for medical purposes.