Was Iran close to building a nuclear bomb before Israel attacked?

As Israeli airstrikes intensify in Tehran and President Donald Trump calls for a full evacuation of Iran’s capital, the world is asking a critical question: How close was Iran to developing a nuclear bomb?

In recent days, Israel has bombed command centers, missile sites, and even state-run Iranian TV during a live broadcast. Iran has responded with waves of missile attacks, and the death toll on both sides is rising rapidly.

While the Israeli government says its strikes have set Iran’s nuclear program back "a very, very long time," the timing and scale of the campaign suggest officials believed Iran was closer than ever to crossing the nuclear threshold.

How close was Iran to building a bomb?

The backstory:

According to reporting from The Associated Press, Israeli Prime Minister Benjamin Netanyahu claimed the campaign was necessary to stop Iran from "getting any closer to building an atomic weapon." Defense officials in Israel say the military destroyed roughly a third of Iran’s surface-to-surface missile launchers and multiple nuclear infrastructure sites in just days.

Meanwhile, Farah N. Jan, a nuclear security expert at the University of Pennsylvania, wrote in an analysis for The Conversation that Israel believed Iran could rapidly assemble up to 15 nuclear bombs.

That belief, Jan said, is what likely prompted Israel to launch what she calls the world’s first "threshold war"—a military strike designed to prevent a country from acquiring nuclear weapons just before it reaches capability.

Jan warned the strategy is inherently unstable. "Iran increasingly believes it cannot deter Israeli aggression without nuclear weapons," she wrote, "yet every step toward acquiring them invites more aggressive Israeli strikes."

What we know:

Iran has significantly enriched uranium in recent years, with International Atomic Energy Agency (IAEA) officials warning it had stockpiled enough material to potentially build several nuclear weapons if it chose to. Israeli strikes have reportedly targeted facilities linked to enrichment and weapons development, with Prime Minister Benjamin Netanyahu claiming the attacks have set Iran’s program back "a very, very long time."

The U.S. intelligence community has maintained that Iran halted its formal nuclear weapons program in 2003, but continued advancing its enrichment capabilities under the framework of civilian use. As of June 2025, Iran had not tested or publicly demonstrated a nuclear device.

• Israel launched the initial strikes on June 13, targeting uranium enrichment sites, nuclear scientists, and senior military officials.
• The head of the International Atomic Energy Agency (IAEA) warned before the attack that bombing Iran could prompt it to withdraw from the Nuclear Non-Proliferation Treaty (NPT), a key global safeguard.
• On June 16, Iran’s government said it was preparing legislation to exit the NPT—effectively removing any international oversight of its nuclear program.
• Iran has long denied it seeks a bomb, but the IAEA says it has enough enriched uranium to build several nuclear weapons if it chooses to do so.

These developments are unfolding rapidly, with both sides escalating military action and political messaging. Trump’s statement adds a new layer of urgency as global leaders try to prevent a broader regional war.

What we don't know:

It remains unclear how close Iran truly was to building an operational nuclear weapon—or how much the recent Israeli strikes have disrupted that timeline. The IAEA has been unable to fully inspect certain sites in Iran since early 2023, limiting independent verification.

It is also unknown whether Iran’s leadership will now pursue nuclear weapons more aggressively as a deterrent, or if diplomatic efforts can still halt further escalation.

With little transparency from Iranian officials and no clear path to diplomacy, the coming days could bring further unpredictability—both on the ground and in global responses.

Trump says "evacuate Tehran" as conflict escalates

President Trump’s warning came from the G7 summit in Canada, where he posted: "Everyone should immediately evacuate Tehran!"

In the same post, he reiterated: "IRAN CAN NOT HAVE A NUCLEAR WEAPON," and blamed Iran for failing to agree to a deal he said would have averted the violence. Trump later left the G7 a day early, citing the conflict.

According to the AP, Israel had already warned up to 330,000 people to evacuate central Tehran before targeting the state television building. Iranian officials say at least four bombs struck the site, briefly disrupting live broadcasts.

Big picture view:

This war, which began as a targeted strike on Iranian nuclear sites, has now morphed into something larger. Iran’s foreign minister said over the weekend that it would stop retaliatory missile launches only if Israel halted its campaign. On Monday, the Iranian Revolutionary Guard vowed its next strikes would be "more forceful, severe, precise and destructive."

As analyst Farah Jan writes, Israel’s preventive strike may ultimately backfire. Rather than stopping Iran’s nuclear ambitions, it could intensify them. She calls it a "commitment trap," in which both sides are locked into escalation—with no easy way to back down.

North Korea, she notes, serves as a cautionary tale: "Despite decades of sanctions and military threats, Pyongyang’s nuclear program has made it essentially immune to preventive strikes. Iranian leaders understand this lesson well."

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