Israel Built Its Case for War With Iran on New Intelligence. The U.S. Didn’t Buy It.
American spy agencies stand by their assessment that Iran hasn’t decided to build a nuclear weapon, but Trump now says Tehran is ‘very close.’
June 17, 2025
Key Points
Experts say Iran’s activities could be part of weapons building or preparatory work to maintain the option of making a nuclear weapon.
WASHINGTON—Before launching its attack on Iran last week, Israel provided the U.S. with intelligence it deemed alarming: Tehran was conducting renewed research useful for a nuclear weapon, including on an explosive triggering system.
But U.S. officials briefed by the Israelis weren’t convinced that the information pointed to a decision by Tehran to build a bomb, according to a senior intelligence official, another U.S. official and two congressional aides familiar with the discussions.
The gap between Israel’s assessment of Iran’s nuclear program and that of the U.S. helps explain why the two allies haven’t been aligned in recent days on dealing with Tehran.
The intelligence Israel shared within the last month covered multiple lines of Iranian research into technology necessary for building a nuclear weapon, according to the U.S. officials. They described “a multi-point initiation system,” a technique used to detonate multiple simultaneous explosions that is used in nuclear bombs, the officials and aides said.
The Israelis also mentioned Iran’s work on neutron particles to generate a chain reaction—a critical part of nuclear fission—as well as on plastic explosives and on integration of fissile material in an explosive device, the U.S. officials said.
The U.S. response was that the intelligence only showed Iran was still researching nuclear weapons, including revisiting work it had done before its nuclear weapons program shut down in 2003, the senior intelligence official and the other U.S. official said.
The U.S. and Israel largely agree that Iran has in recent months put itself in a stronger position to build a nuclear bomb. Iran has long insisted its nuclear program is for peaceful purposes.
The U.S. has said publicly that Iran has conducted scientific and engineering work that could make it easier to construct a nuclear device. The U.S. estimates that it would probably take Iran one to two weeks to produce enough weapons-grade enriched uranium for a nuclear weapon, and U.S. officials have said Iran could build some kind of crude nuclear weapon in a few months.
But the consensus view among U.S. intelligence agencies is that Iran hasn’t made a decision to move forward on building a bomb, an assessment Director of National Intelligence Tulsi Gabbard repeated in public testimony to Congress in March.
Asked Tuesday on Air Force One about Gabbard’s earlier testimony, President Trump replied, “I don’t care what she said, I think they were very close to having them.” His return to Washington early from a G-7 meeting in Canada had “nothing to do with a cease-fire,” he said.
Trump’s view that Iran is near to getting a bomb is shared by some other administration officials. “We believe that Iran is as close to having a nuclear weapon as one can get. They have all the components necessary to put one together,” a senior administration official said.
Gabbard told CNN Tuesday that she and Trump were “on the same page” on Iran’s nuclear activities.
Jeffrey Lewis, a nuclear expert at the Middlebury Institute of International Studies, said the scientific work Iran was conducting didn’t point to an imminent Iranian sprint to acquire a nuclear weapon. “This all looks like research,” he said, though he added, “Iran definitely wants a bomb option.”
Before the first bombs fell last week, Trump urged Israel to hold off on strikes, asking Israeli Prime Minister Benjamin Netanyahu to let a diplomatic process over Iran’s nuclear program play out. But as the conflict has worn on, Trump has voiced more concern about Iran’s pathway to a nuclear weapon.
The U.S. intelligence community assesses that Israel’s campaign so far had set Iran’s nuclear work back by about five to six months, the senior U.S. intelligence official said, adding that the damage could grow as Israel’s campaign continues.
Netanyahu has publicly painted the intelligence as a clear indicator of Iran’s intent to make a nuclear weapon.
Iran was secretly working to weaponize uranium and “would achieve a test device, and possibly an initial device, within months, and certainly less than a year,” he said in a Sunday interview with Fox News. Israel could no longer hold off on attacking Iranian nuclear sites to prevent its nuclear breakout, he said.
Netanyahu also asserted that Iran intended to give nuclear weapons to its Houthi proxies in Yemen, a statement multiple U.S. intelligence officials described as surprising since they had no information to support.
“The Israelis could be drawing worst-case scenarios from bits of intel or exaggerating to suit their purposes,” said Philip Gordon, who served as Vice President Kamala Harris’s national security adviser.
Experts say the activities Israeli officials detailed could be part of an active nuclear weapons building program, but could also be preparatory work to maintain the option of making a nuclear weapon. Iran still must assemble and integrate the parts of a nuclear weapon into a warhead, said David Albright, president of the Institute for Science and International Security.
Gen. Erik Kurilla, commander of U.S. Central Command, told the Senate Armed Services Committee last week that Iran is “mere steps” away from having uranium enriched to the weapons-grade level of 90%. If Iran decided to assemble a bomb, he continued, it could have the first 55 pounds of weapons-grade material “in roughly one week and enough for up to 10 nuclear weapons in three weeks.”
Gabbard, in her March testimony, also said Iran’s “enriched uranium stockpile is at its highest levels and is unprecedented for a state without nuclear weapons.”
The U.S. intelligence community said last July in a report to Congress that Iran has “undertaken activities that better position it to produce a nuclear device, if it chooses to do so.” The report omitted what has been a standard U.S. intelligence assessment for years that Iran “isn’t currently undertaking the key nuclear weapons development activities necessary to produce a testable nuclear device.”
Tehran is signaling it is open to resuming nuclear talks with the U.S. in return for a halt to the Israeli strikes. Iranian officials said they think Israel would need U.S. help to do meaningful damage to targets, such as the Fordow uranium-enrichment facility, which is buried under a mountain.
Write to Alexander Ward at alex.ward@wsj.com, Lara Seligman at lara.seligman@wsj.com and Dustin Volz at dustin.volz@wsj.com
Israel shared intel with the U.S. regarding Iran’s nuclear research, including alleged work on an explosive triggering system.
U.S. officials don’t believe the intel indicates Iran decided to build a bomb, creating a gap in assessment between the allies.