NEWS

We have no idea if Iran can still build a bomb

by | Apr 9, 2026

Poster of Mojtaba Khamenei over a square in Tehran

Members of the Iranian security forces stand guard under a large portrait of Iran’s new Supreme Leader, Mojtaba Khamenei, during a memorial to mark the 40th day since his father, Ali Ayatollah Khamenei, was killed in US-Israeli joint strikes, on April 9, 2026, in Tehran, Iran. | Majid Saeedi/Getty Images

The focus of the US-Iran war — and now the negotiations over the US-Iran ceasefire — has shifted to Iran’s control of the Strait of Hormuz, to such an extent that the main original justification for the war (destroying Iran’s nascent nuclear program) can sometimes feel like an afterthought. 

It’s not clear to what extent it’s still even a priority for the US government. On Wednesday, Secretary of Defense Pete Hegseth insisted that Iran’s nuclear program would still be dismantled while Vice President JD Vance, who is leading ceasefire talks in Pakistan this weekend, suggested he’s not concerned about Iran forsaking its right to nuclear enrichment. Meanwhile, President Trump has suggested at various points that this is a moot point, since Iran’s nuclear program has been irreparably destroyed anyway. (It should be noted: He made the same claim after the airstrikes on Iran in June.) 

Does Iran still have a pathway to a nuclear weapon? If it does, can the US and Israel do anything about it? To help sort through the confusion, I spoke with Jeffrey Lewis, a professor at the Middlebury Institute’s James Martin Center for Nonproliferation Studies. Lewis is an expert on nuclear nonproliferation and a leading open source analyst studying the nuclear and military capabilities of countries like Iran and North Korea. 

This conversation has been edited for length and clarity.  

On Wednesday, we heard Secretary of Defense Pete Hegseth, Israel’s Benjamin Netanyahu, and others insist that Iran must turn over its remaining uranium stockpile and dismantle its enrichment program. They also say it could still be removed by force if Iran didn’t agree. Is that remotely realistic? 

It’s realistic if we occupy the country, but short of that, no. The claim we’ve heard is that half the highly enriched uranium is at [the underground tunnel complex in] Isfahan. So, where’s the other half? And if it’s not all at Isfahan, then how many other sites is it at? Is some of it still at Fordow and Natanz? Is it at some third location? What about their ability to produce centrifuges? What about centrifuges they have in storage? What about the people who know how to operate them?

 You can set them back by destroying things, immobilizing things, and taking things, but there’s a large group of people who understand how to operate these things. There’s a basic capability that’s in place. 

And oh, by the way, the neighbor who has been handling the ceasefire negotiations [Pakistan] happens to have a very large and capable centrifuge program that was the source of Iran’s original centrifuges. So, what’s the plan here, guys?

In his speech last week, Trump said that Iran’s “nuclear dust” — as he called it — was buried far underground and unusable. Is there anything to that claim? 

There’s no evidence of that. I mean, we see the tunnels. The tunnels are intact, so it’s not buried. The only burying was the Iranians burying the entrances to protect them, but we’ve seen them open those entrances and access the tunnels. If you put something in a safe in your house, it doesn’t mean that you can’t get to your money, right? You just have to open the safe.

Sure, but given the level of satellite surveillance Iran is under, and the level of US and Israeli intelligence penetration into the Iranian regime, isn’t there a case to be made that it would just be crazy for the Iranians to try to restart their nuclear program now?

The intelligence penetration was real. Is it still real? No one knows that. The surveillance is not anything like 24/7. We’re getting satellite images taken some number of times a day, and there’s some latency. But unless we are operating drones 24/7 over those sites, we’re not going to be able to know for certain unless the Iranians are really slow. 

If they were to open up the tunnels, I don’t think it would take them that long to move the [stockpile]. So if we saw them opening up the tunnels, that could cause a race to hit them. But it’s also true that we saw them opening up the tunnels back in September and October, and we didn’t do anything about it.

Just as a broad statement, I’m not as confident as [the US and Israeli governments] are that they know where all the material is. I’m not as confident as they are that they could detect a movement of the material. 

On Tuesday, when we saw Trump threaten to destroy a whole civilization, it got to the point that the White House actually had to deny that it was considering nuclear weapons use, and people like Tucker Carlson were calling on officials to disobey nuclear orders. I’m curious what you made of that as someone who considers nuclear risk on a regular basis.

I didn’t think that they were going to use nuclear weapons, and I didn’t interpret that as a nuclear threat. Trump likes bombast, and I took him to mean striking bridges and power plants — which is arguably illegal, and I certainly am morally uncomfortable with it.

But, you know, nuclear weapons would be useful for targeting the deep underground facilities. They would be very useful for these missions. I’m glad that the US has not used them, and I think it would be a terrible mistake to do that. But it does cross my mind that the uranium that I think is not buried in rubble could be buried in rubble if they hit Isfahan with a nuclear weapon, which I don’t want them to do. 

There’s still a taboo there, but I don’t know how strong that taboo is. 

When it comes to Iran’s missile program, the Pentagon has put out a lot of figures on the numbers of missiles and drones and launchers destroyed, but how much do we actually know about the capabilities Iran still has after being hit for almost 6 weeks? 

The problem is, we didn’t have a good baseline for how many launchers, how many missiles, there were [at the outset].

Those kinds of estimates are always a bit of voodoo. We don’t make them on the open source side, because we don’t think we can do it reliably. When you have a factory that’s operating [making drones or missiles], unless you try to count every box that goes in and every box that comes out, it’s pretty hard to know. 

It’s also hard to know what you’ve destroyed. I mean, the Iranians are almost certainly using lots of decoys, which the Serbs did in the 90s. That’s not to say that these are all decoys that are getting struck, but until you go in on the ground, it becomes really hard to know.

What lessons do you think other potential nuclear proliferators might take from this war?

That it makes sense to finish that nuclear weapon as soon as you can. I would certainly look at the three countries that disarmed — Iraq, Libya, and Iran — or at least made disarmament agreements; the US double crossed all of them. And then, I would look at North Korea, and they seem to be fine. I’d rather be North Korea or Pakistan than I would Iran, Iraq, or Libya.

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