Why It Matters

A recent Congressional Research Service report on Iran's nuclear program raises questions for Congress and the Trump administration about verification, oversight, and the status of Tehran's nuclear capabilities following U.S.-Israeli strikes and years of reduced international monitoring.

The report, Iran and Nuclear Weapons Production, was updated July 13. CRS notes that the status of Iran's nuclear program remains unclear because International Atomic Energy Agency (IAEA) inspectors have lacked access to key facilities and because the effects of U.S.-Israeli strikes are uncertain.

The Big Picture

The decision to pull out of the 2015 Joint Comprehensive Plan of Action (JCPOA) set the stage for the current uncertainty. The first Trump administration withdrew from the accord in May 2018, after which Iran progressively stopped implementing many of its commitments. Beginning in July 2019, the IAEA verified that some Iranian nuclear activities exceeded JCPOA limits. By February 2021, Iran stopped allowing the agency to conduct the verification and monitoring required by the agreement.

Before the June 2025 strikes, Iran's installed centrifuges, enriched uranium stockpile, enrichment levels, and number of enrichment locations exceeded JCPOA limits. The Defense Intelligence Agency assessed in May 2025 that Iran probably would have needed less than one week to produce enough weapons-grade highly enriched uranium for one nuclear weapon. That estimate concerned production of fissile material, not the time needed to construct a functioning nuclear weapon. The JCPOA had scheduled some key enrichment restrictions to begin expiring in January.

The report also emphasizes that U.S. intelligence assessments have not established that Iran was actively building a nuclear weapon. A 2025 public intelligence assessment stated that Iran was "not building a nuclear weapon" and that its supreme leader had not reauthorized the weapons program suspended in 2003. IAEA Director General Rafael Grossi likewise said in March that the agency had no information in June 2025 indicating a structured, systematic Iranian program to build a nuclear weapon. The current assessed timeline for weaponization remains unclear.

The IAEA withdrew inspectors from Iran after the June 2025 U.S.-Israeli airstrikes on Iranian nuclear facilities. U.S. and Israeli forces carried out additional strikes beginning Feb. 28, but CRS says the extent to which either round of attacks affected Iran's ability to produce nuclear weapons remains unclear. The IAEA officially reported that it withdrew its inspectors by the end of June 2025 for safety reasons.

Iranian Foreign Minister Seyed Abbas Araghchi said March 15 that the country's enriched uranium was "under the rubble" created by the June 2025 attacks and that Iran had "no plan" to recover it. CRS also notes that U.S. and Iranian officials have said Iran has not resumed enriching uranium this year. The IAEA estimates Iran's remaining stockpile includes 440.9 kilograms of uranium hexafluoride enriched up to 60% uranium-235 and 184.1 kilograms enriched up to 20%.

The Bottom Line

The report notes but does not evaluate the enforceability or verification provisions of the June memorandum of understanding between the United States and Iran. The agreement states that "Iran reaffirms that it shall not procure or develop nuclear weapons," while CRS concludes that significant uncertainty remains over the condition of Iran's nuclear infrastructure, the location and accessibility of its enriched uranium, and any Iranian plans to develop a nuclear weapon.

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