What do we actually know about Iran's nuclear program? Not much.

Last summer’s air strikes on Iran’s nuclear facilities failed to resolve the nuclear issue. Instead, they clouded the situation.

When Israel attacked Iranian nuclear facilities, the International Atomic Energy Agency (IAEA) ceased all on-site verification and monitoring activities in Iran; by the end of that month, it had pulled all inspectors out of the country for safety reasons.

This loss of oversight is the key context for the war launched by the U.S. and Israel late last month. The campaign is not a necessary response to an imminent Iranian bomb, but rather a discretionary escalation in which Tehran’s nuclear program supplied the most persuasive justification for what appears to be a regime change operation.

The timeline is crucial. In June 2025, before the “Twelve-Day War,” the IAEA Board of Governors found Iran in non-compliance with its safeguards obligations but also stressed support for ongoing U.S.-Iran talks. Oman had just confirmed another round of negotiations in Muscat. The next day, Israel attacked.

The current conflict followed the same pattern. On February 27, 2026, the Omani Foreign Minister stated that the latest U.S.-Iran talks in Geneva had made significant progress and that technical discussions would continue in Vienna the following week. Rafael Grossi, the IAEA director general, said he personally joined the two most recent rounds to offer technical advice.

An Israeli defense official, by contrast, told Reuters that the February 28 operation was coordinated with Washington, had been planned for months, and had a launch date fixed weeks in advance. This is not the timeline of a war triggered by a suddenly discovered nuclear emergency; it is the timeline of a war chosen while diplomacy was still ongoing.

None of that means Iran’s nuclear program was benign. Before the June 2025 strikes, the IAEA estimated Iran had accumulated 440.9 kilograms of uranium enriched to 60 percent U-235. If further enriched to weapons-grade, this is enough for about ten nuclear weapons, according to the agency’s standards. In May 2025, the IAEA also determined that three undeclared sites were part of a structured weaponization program conducted until the early 2000s. At Lavisan-Shian, a former nuclear site in Tehran, the agency assessed that undeclared uranium metal was used in 2003 to produce neutron initiators for scaled implosion tests. Iran was, and still is, a real proliferation threat.

But danger is not the same as imminence. The public record before this war showed an advanced threshold capability, not a demonstrated rush to build a bomb. The U.S. intelligence community’s 2025 threat assessment stated that Iran was not constructing a nuclear weapon and that Ayatollah Ali Khamenei had not reauthorized the weapons program suspended in 2003.

The Defense Intelligence Agency was similarly clear: Iran was “almost certainly” not producing nuclear weapons, even though its enrichment progress had likely decreased the time needed to make enough weapons-grade uranium for a first device to less than a week. The IAEA’s May 2025 assessment said it had no credible indications of an ongoing nuclear weapons program. The key difference, then, was between a serious threshold capability that demanded tighter verification and an imminent weapons threat that might justify preventive military action.

That distinction matters because the stated reason for the current war quickly extended beyond nonproliferation. In briefings to Congress, Pentagon officials acknowledged there was no intelligence indicating Iran planned to attack U.S. forces first, despite earlier claims to the contrary.

President Trump, meanwhile, described the campaign in broader terms: preventing an Iranian bomb, destroying missile capabilities, and neutralizing wider threats to the United States and its allies. He then went even further, demanding Iran’s “unconditional surrender” and saying Washington should help choose Iran’s next leader. Once that becomes the language of war, the nuclear issue is no longer the entire casus belli. It is simply the most defensible public justification for a campaign whose goals are already expanding.

This is a major problem from a nonproliferation standpoint. The key requirement for a serious Iran policy is verifiable knowledge about the location of uranium, its form, whether enrichment continues, and the remaining centrifuge capacity. As of late February 2026, the IAEA reported that it had no access to any of Iran’s four declared enrichment facilities. It said it did not know whether the newly declared Isfahan Fuel Enrichment Plant, located within Iran’s nuclear complex in central Iran, contained nuclear material or was operational.

The agency also said it could not provide information on the current size, composition, or whereabouts of Iran’s enriched uranium stockpile, nor could it verify whether Iran had suspended enrichment-related activities. And, because it has lacked access since February 2021 to centrifuge component manufacturing, assembly, and testing workshops, it was unable to provide information on Iran’s current centrifuge inventory. This is not the mark of success in a nuclear crisis. It is only what success looks like if one mistakes visible damage for verifiable constraint.

Nor is there much reason to believe that air power can solve the constraint problem. A preliminary U.S. intelligence assessment in June 2025 found that the earlier U.S. strikes probably only delayed Iran’s program by a few months. Grossi has now emphasized the larger point with particular clarity, saying that military escalation was delaying “indispensable work towards a diplomatic solution for the long-term assurance that Iran does not acquire a nuclear weapon.”

Even the latest fighting highlights the limits of force. The IAEA states that recent strikes damaged entrance buildings at Natanz, Iran’s main enrichment complex in central Iran. But there is no evidence for claiming that the deeper verification problem has been solved. Bombing can crater entrances. It cannot, by itself, block Iran’s path to a nuclear deterrent.

The real issue is that the war has made monitoring the nuclear program more difficult, not easier. A serious nonproliferation strategy would have aimed to roll back Iran’s dangerous proximity to a nuclear weapon through tighter inspections, clearer limits, and more reliable warning times. Instead, this war has done the opposite. It has traded transparency for destruction, verification for guesswork, and diplomacy for a widening conflict whose nuclear outcome is now less certain than before. This does not solve the nuclear problem. It makes the next decision point more dangerous than the last.