There’s More Work to Do on Iran

Now that the dust has settled from the American and Israeli strikes on Iran’s nuclear weapons program, it seems very likely that the Islamic Republic retains enough material and know-how to resume working toward the ultimate weapon if it so chooses.

To be sure, Iran’s production chain for a bomb is broken at several critical points. Its uranium mines, and its declared mill to turn their ores into yellowcake, seem intact. However, its sole known facility for the next step, converting this powder into uranium gas for enrichment, is out of operation—as are its official enrichment plants at Natanz and Fordow.

The same goes for the metallurgy facility to transform enriched uranium into something usable in an actual weapon, and for multiple laboratories deemed to be working on that device. Likewise, many of the top scientists and project managers overseeing these efforts are now gone.

But Iran spent more than two decades developing secret and redundant infrastructure to ensure the overall program survives such breaks in the chain. And it may have used crucial hours and days during the conflict to boost this survivability.

Of utmost concern is the fate of its highly enriched uranium (HEU) stockpile, at least 10  bombs’ worth on the eve of the strikes. There are several plausible scenarios where critical amounts of this material could have survived the conflict. Iran’s foreign minister said the country relocated this stockpile at the outset of Israeli operations, before any bombs fell on its HEU bunker at Isfahan. Western intelligence agencies and International Atomic Energy Agency (IAEA) inspectors publicly suspect as much. Even if unlikely, another “known unknown” is whether Iran removed any HEU from Fordow prior to U.S. airstrikes. 

Senior Israel officials admit much of the material likely remains in situ underground at Fordow, Natanz, and/or Isfahan. As Prime Minister Benjamin Netanyahu said recently, “The one thing that we didn’t deal with, that we knew we didn’t deal with, was the enriched uranium.”

Resolving these questions still would not close the case, even if Iran cannot access any buried stocks. American officials believe Isfahan held only about 60 percent of Iran’s known enriched product, and the IAEA has warned for years that it cannot account for Iran’s entire enriched stockpile. Nor can it rule out some fraction being stored at the deeply buried “Pickaxe” site next to Natanz that remains uninspected and undamaged. Top Trump administration members have  speculated openly on the stockpile’s current status, and CIA Director John Ratcliffe asserted only that the “vast majority” is “likely buried at Isfahan and Fordow.” There is a core concern, as Republican lawmakers briefed by the executive branch put it, that “getting rid of the nuclear material was not part of the mission” and “most of it’s still there. So we need a full accounting.”

That full accounting extends beyond HEU stocks, with American officials positing that covert facilities of one kind or another remain operational. And claims that “Iran will never obtain a nuclear bomb, because Operation Midnight Hammer obliterated their nuclear capabilities,” in the words of White House spokeswoman Anna Kelly, elides narrow tactical effectiveness and broader strategic conclusiveness. Like maximal assertions from the president, Defense Secretary Pete Hegseth, and others that Iran’s program is “destroyed,” this statement makes no mention of sites untouched by U.S. airstrikes, nor of possible Iranian steps to mitigate the impacts of those strikes. It is noteworthy that President Trump reportedly rejected a plan from U.S. Central Command to target three additional sites, and to hit several targets repeatedly, in order to more assuredly degrade or end Iran’s nuclear weapons program.

The president’s shorthand comparison of the U.S. attacks on Iran to those on Hiroshima and Nagasaki underlines this sense of overstatement. It also is freighted with incredibly relevant, if unintended, implications. By themselves, those two bombs did not convince Tokyo to sue for peace. That war ended because Imperial Japan faced concentric and tightening pressures that gave no hope of relief and made defiance untenable. Such strategic claustrophobia is still largely abstract for the Tehran regime.

Indications abound that Iran retains residual ability, at least around key margins, with which to reconstitute its bomb-building effort. And, crucially, it might not require further uranium conversion or enrichment. Iran reportedly has pursued a crude but testable device for its existing uranium trove. And despite its metallurgy and suspected bomb-making sites being hit hard, Tehran’s extensive undeclared—and unresolved—activities on these fronts raise serious concerns about leftover, covert weaponization capabilities.

Nor would Iran need much to complete the most worrisome enrichment. Airstrikes neutralized much, but reportedly not all, of Iran’s known centrifuge industry, and IAEA Director Rafael Grossi said that Iran could plausibly have a couple hundred centrifuges up and running in a matter of months. In a familiar pattern, his agency also believes the regime socked away spare machinery and parts. With one-tenth of its pre-conflict HEU stocks, some 40-odd kilograms, Iran could produce its first bomb’s worth of 90 percent enriched uranium in a few weeks.

Such a dash could be concealed relatively easily, involving perhaps one-tenth the floor space of Fordow’s recently active enrichment hall, and far less still than the erstwhile underground Natanz plant. Plausibly this could occur at Pickaxe, which the IAEA says hosts “numerous and important” nuclear activities; at the newly divulged Isfahan enrichment site that apparently weathered the conflict; or some as-yet-undetected hideaway. (It’s worth noting that all of Iran’s known enrichment facilities were built secretly before being discovered.)

These uncertainties should inform new estimates of Iran’s distance from the atomic threshold. The regime now might be years from a bomb, as the Pentagon spokesperson recently estimated, or delayed by several months, according to French intelligence. Ongoing assessments of battle damage could sharpen the precision and consensus of these projections.

But for better or worse, technical realities alone will not determine what comes next. Even with their program profoundly diminished, it must be assumed that Iran’s surviving and future scientists could engineer a rudimentary test device. Such an Iranian Alamogordo would resemble not only America’s crash program to cross the finish line, but also the first Soviet, French, and Chinese mushroom clouds that burst so unexpectedly in remote desert expanses.

The regime could perceive this fait accompli as vital to restore its deterrence and sense of invulnerability that were so swiftly shattered alongside its prized missiles and air defenses. If recent decrees to the IAEA are any hint, it will do so by redoubling its nuclear program’s best remaining asset—opacity. Not coincidentally, the agency found Iran in breach of its safeguards right before the first Israeli warplanes were airborne. American and Israeli operational achievements have not obviated those concerns.

Quite the opposite. Iran suspended all remaining cooperation with the IAEA in the wake of the conflict. This further complicates the hunt for its HEU stockpiles, clarity on how far its program has been set back, and efforts to detect any future reconstitution. Iran now demands recognition of its supposed right to enrich before inspections can resume and, if past practice is any guide, restored access would still be far too limited to discern its bomb-making ability and ongoing ambitions. In accusing the IAEA of enabling Israeli-U.S. attacks by censuring its nuclear program, Iran also builds counterpressure against new military action to stop its reconstitution. Meanwhile, military and political leaders in Tehran make plain their intent to rebuild.

This is where America’s newfound credibility on deterrence can be pivotal. For the first time, the regime must weigh its enduring nuclear ambitions against the unfamiliar anticipation of military interdiction. President Trump’s vows of follow-on strikes certainly are helpful here. But they must be consistent and conditioned on more than just renewed enrichment, since Iran might be able to sneak toward the bomb without spinning up a single additional centrifuge.

And the involvement of the IAEA is vital here. The president, in close coordination with Israel as well as Britain, France, and Germany—the European signatories to the Obama-era Iran nuclear deal—should link further action explicitly to Iran’s full, immediate, and unconditional compliance with its IAEA safeguards obligations. This will leave Tehran far less wiggle room and time to rejuvenate its program surreptitiously and erode U.S. deterrence diplomatically. Having dealt significant yet reversible setbacks to Iran’s nuclear weapons ambitions, it is now incumbent on the United States and its partners to end the regime’s illegal and secret program more verifiably and permanently.