The June 2025 operations against Iran’s nuclear program, Rising Lion and Midnight Hammer, were widely hailed as an operational victory, but the true measure of strategic success hinges on a murkier question: did the strikes merely delay Iran’s nuclear program by months or dismantle it for years? Whether the strikes obliterated facilities, rendered the stockpile inaccessible, or left underground infrastructure intact will define how long the setbacks last, and in turn, follow-on military action. Despite unified public messaging from President Trump and Prime Minister Netanyahu, intelligence from Washington and Jerusalem tells a more fragmented story. Although based on leaks, public statements, and unofficial sources, these assessments suggest differing U.S. and Israeli intelligence perspectives shaped by contrasting doctrines, risk tolerance, and assumptions. These disparities raise three critical questions: What drives the contrasting assessments between the two allies? What is the best open-source estimate of Iran’s current breakout time? And will additional strikes be necessary to destroy Iran’s nuclear program? Before the Strikes: Differing U.S. and Israeli Assessments on Iran Before the June 2025 strikes, U.S. and Israeli assessments of Iran’s nuclear program relied on shared intelligence pointing to potential weaponization activity (e.g., high-explosion experiments, gathering groups of nuclear scientists, and advanced computer modeling) but drew different conclusions due to contrasting assumptions, perceived urgency, and military doctrines. Ultimately, U.S. analysts prioritized caution and more conclusive indicators of weaponization, while Israeli intelligence favored early warning and preemptive action. By March 2024, U.S. and Israeli sources reportedly found Iran had been conducting new computer modeling and experiments (including multi-point detonation tests, production of plastic explosives, and neutron radiation trials), which could accelerate the path to a crude nuclear bomb. According to Axios, U.S. officials maintained that weaponization had not resumed since 2003, though ODNI quietly dropped the standard post-JCPOA threat assessment line that Iran was “not currently undertaking the key nuclear weapons-development activities necessary to produce a testable nuclear device.” Israeli intelligence officials reportedly grew more concerned, especially after the October 7 intelligence failure, and began seeking U.S. backing on a potential strike. In October 2024, following signs that Iran allegedly resumed high-explosive research, Israel destroyed the suspected Taleghan 2 facility at Parchin. By February 2025, joint intelligence apparently detected a team of Iranian scientists exploring a faster, cruder weaponization path. According to the Washington Post, U.S. intelligence in the second Trump administration still assessed Iran was not actively weaponizing. Both countries agreed that Iran’s stockpile and centrifuge capabilities allowed for a rapid breakout, but they disagreed on how weaponization would unfold. U.S. intelligence estimated Iran would need 1-2 weeks to produce enough weapon-grade uranium and at least three months to assemble a deliverable weapon. Mossad, however, assessed Iran could build a crude nuclear device in 15 days. The divergence reflects differing assumptions: U.S. analysts tend to frame timelines around launching a deliverable nuclear weapon (accounting for the steps of weaponization, testing, and developing delivery systems), while Israeli timelines focus on when Iran could deploy a rudimentary nuclear device. Post-Strike Assessments: Disputes over the Impact of Operations Rising Lion and Midnight Hammer Initial leaked Israeli, U.S., and IAEA intelligence assessments suggest that both operations inflicted significant damage across Natanz, Fordow, and Isfahan, though falling short of Prime Minister Netanyahu and President Trump’s claims of “consigned Iran’s nuclear program to oblivion” and “total obliteration.” Israel’s emerging intelligence assessment allegedly concluded that Natanz’s aboveground facilities were “completely destroyed,” Fordow suffered “major damage,” and Isfahan’s uranium reprocessing facility “was destroyed.” As for underground facilities, officials reportedly said signs “point to collapse of [Natanz’s] underground infrastructure”), noted uncertainty over whether underground areas [at Fordow] suffered full structural collapse,” and stated at Isfahan, while there is “damage to underground tunnels,” “the full scope is still being assessed.” Israeli officials assess that uranium was not moved and is now buried under Isfahan and Fordow – a view affirmed by the Israeli Atomic Energy Agency, whichstated the damage could persist “if Iran does not get access to nuclear material.” In the U.S., Joint Chiefs Chairman Caine noted all three sites “sustained severe damage and destruction,” but deferred to the intelligence community to assess specific damage. The Defense Intelligence Agency (DIA)’s leaked “Battle Damage Assessment” found only months-long setbacks, with some centrifuges intact, and the lower structures of Fordow and Isfahan operational despite caved-in entrances. Like most initial assessments, it was based on limited and potentially incorrect information and treated as a low-confidence judgment subject to change as more information became available. U.S. officials’ assessments on the status of Iran’s uranium stockpile have evolved in the week following Operation Midnight Hammer. In an interview the morning after the U.S. strikes, Vice President Vance first suggested Iran relocated its stockpile, while later in the week, Secretary Hegseth, Marco Rubio, and President Trump indicated that nuclear material remained at the facilities throughout the strikes. In recent days, Secretary Rubio and JD Vance have argued that regardless of the status of the stockpile, the program is “obliterated,” claiming “mission success” because the U.S. removed Iran’s path to a nuclear weapon when destroying Iran’s conversion facility and enrichment facilities. IAEA Director General Rafael Grossi testified it is “extremely unlikely” that centrifuges survived at the three sites, given the equipment sensitivity and the payloads utilized. The IAEA noted that strike holes were aligned with underground halls at Natanz, targeted one road and entrance at Fordow, and hit entrances to tunnels used for the storage of enriched uranium at Isfahan. Grossi also noted that on June 13 (the first day of Israeli strikes), Iran’s foreign minister notified him that the country had taken “special measures to protect nuclear material,” which he interpreted as having moved it. Differences between U.S., Israeli, and IAEA initial assessments may stem from prioritization of certain data types and assumptions about how Iran would resume its nuclear program. While Washington and Jerusalem share intelligence, their agencies may prioritize or interpret data differently. Mossad, which relies more heavily on human intelligence, reportedly had operatives on the ground during and after the strikes (as IDF Chief of Staff Lt. Gen Zamir confirmed), giving Israel a unique vantage point into what may be destroyed or buried. President Trump hinted at this in his NATO speech, notingMossad operatives had already visited Fordow. In contrast, at this stage, U.S. and IAEA assessments might be placing more weight on satellite imagery and seismic data. In addition, there may be differing assumptions about Iran’s likely response and strategy for rebuilding. Israeli assessments use the phrase “non-operational,” with Mossad allegedly assuming Iran will abandon Fordow, Natanz, and Isfahan, shifting instead to new sites. In contrast, U.S. intelligence appears to treat the strikes as temporary “setbacks,” assuming it will return to and repair the sites, as evidenced by statements from DNI Tulsi Gabbard and House Foreign Affairs Chair Michael McCaul. Estimating Breakout Timelines At this stage, any technical estimate of Iran’s breakout time will be highly speculative, as accuracy depends on several unresolved variables, including Iran’s undeclared centrifuge inventory, the condition of its uranium stockpiles, and its ability to rebuild advanced cascade setups. Breakout time refers to the time needed to produce enough fissile material for one nuclear weapon (approximately 25 kg of 90% highly enriched uranium), excluding weaponization research, miniaturization, and testing a deliverable. An added challenge is that Iran’s breakout timeline also depends on rapidly evolving domestic factors (e.g., including paranoia, bureaucratic friction, knowledge loss after assassinations of nuclear scientists, and procurement challenges) that are difficult to account for in technical estimates. While estimates will surely vary widely, Table 1 outlines only two of many possible technical breakout timelines, each relying on different assumptions about what capabilities Iran retained after the strikes. In the first scenario, where Iran retains access to its entire stockpile (as suggested by some U.S. and IAEA officials), the breakout time for one weapon could be roughly 1 to 3 months. Iran reportedly has thousands of centrifuges stored in alternative locations, which would potentially be enough to create multiple cascades. Experts then estimate that it could take Iran roughly six weeks to install nine cascades of IR-6 centrifuges, with an additional 60 days to enrich all 400 kg of 60% stock to weapon-grade or 5-10 days to produce one weapon. In the second scenario, where Iran’s 20% and 60% stockpiles were destroyed or buried, as suggested by Israel, the breakout estimate could extend to at least 6-12 months. Iran could need to resume enrichment from lowly-enriched uranium (2-5%), setting its stockpile back to where it was in November 2020. To produce enough fissile material for one weapon, Iran could likely need to build 15-20 interconnected cascades, grouped in three enrichment stages. The first step, still assuming it has thousands of undeclared centrifuges, could be rebuilding its enrichment capacity, which could take anywhere from six months to one year (assuming Iran has degraded capacity to only 75-100 centrifuges per month, and most of its undeclared centrifuges are advanced). Building on expert estimations that Iran can set up approximately 6.3 cascades per month, and using a similar setup to its IR-6 setup at Fordow, this step could be completed in 10-12 weeks. Based on Iran’s enrichment patterns at Fordow over the last three quarters, the full enrichment process across the three stages (at peak performance) could take one to two months. Are Further Strikes Necessary? Whether further strikes are necessary will hinge on what level of military dismantlement will satisfy Israeli security and U.S. negotiating goals. Three unresolved questions are likely to shape this decision: Iran’s stockpile, the effectiveness of strikes on underground facilities, and the number of undeclared centrifuges Iran has. First, assuming U.S. (and now European) assessments are correct that Iran has maintained its stockpile, then deciding how to eliminate this will likely influence both American and Israeli strategies. Although Iran has lost centrifuges at its Fordow, Natanz, and Isfahan, it also likely has an undeclared stockpile of centrifuges. Iran has not permitted the IAEA to monitor or verify centrifuge production since early 2021, so the agency does not know how many centrifuges Iran has outside of its two declared enrichment plants. As demonstrated above, with nine cascades of IR-6 centrifuges and 60% enriched uranium, Iran could enrich to weapons grade and build a crude nuclear device. For Israel, already skeptical of a limited nuclear deal, and despite the U.S. potential preference to include the stockpile as a prerequisite to negotiations, destroying the stockpile through airstrikes is likely seen as the most reliable way to prevent a rapid breakout. Second, so far, U.S. and Israeli intelligence have been uncertain about the effectiveness of strikes on underground areas at Fordow and Isfahan. For example, the DIA leak noted that the U.S. struck Isfahan with only Tomahawk missiles, not bunker busters, because “there was an understanding that the [GBU-57] would likely not successfully penetrate Isfahan’s lower levels, which are buried even deeper than Fordow.” Should this be accurate, without a bomb stronger than the GBU-57, Israel would be less likely to strike (unless to delay facility operations by targeting entrances, exits, or roads) but rather send commando units. A third concern is that Iran had covert weaponization research and enrichment sites, which it had not activated ahead of the strikes. Iran announced in early June that it had built and would activate a third enrichment site. Although the site’s location is unconfirmed, Director General Grossi identified it as Isfahan, while others suggested Pickaxe Mountain, a 100-meter-deep site which is even more fortified than Fordow. Regardless of where Iran moves next, Israeli leaders remain wary that Iran may disperse its nuclear activities across small covert sites. Should such credible evidence emerge, especially before Iran can restore its S-300 air defenses (which previously took about 7 months), Israel could resume strikes to prevent Iran from rebuilding.