Fact: An Iranian nuclear weapon is not imminent.  U.S. and Israeli intelligence assess that Iran is not actively building a bomb, and that it would take Iran at least two to three years to have a deliverable weapon.

Since at least 1993, Israeli political leaders have warned the United States that a nuclear-armed Iran was imminent, as noted by U.S. diplomatic cables:

  • 2005: A few GOI [Government of Israel] officials admitted informally that these estimates need to be taken with caution. The head of the MFA’s [Ministry of Foreign Affairs] strategic affairs division recalled that GOI assessments from 1993 predicted that Iran would possess an atomic bomb by 1998 at the latest.
  • 2009: “Israel continues to offer a worst-case assessment of the Iranian nuclear program, emphasizing that the window for stopping the program (by military means if necessary) is rapidly closing. … (COMMENT: It is unclear if the Israelis firmly believe this or are using worst-case estimates to raise greater urgency from the United States).”

Secretary of Defense Leon Panetta has explained that, were Iran to decide to construct a nuclear weapon, it would take Iran up to three years to actually build one given current capabilities:

  • Panetta: “The consensus is that, if they decided to do it, it would probably take them about a year to be able to produce a bomb and then possibly another one to two years in order to put it on a deliverable vehicle of some sort in order to deliver that weapon” (60 Minutes; June 10, 2012)

Director of National Intelligence James Clapper implied it would take even longer when testifying before Congress.  Asked by Senate Armed Services Chairman Carl Levin about whether he disagreed with Panetta’s timeline, he said:

It is also critical to note that these timelines don’t begin until Iran has made the decision to build a nuclear weapon.

The path to a producing a nuclear weapon would involve several steps for Iran that have not been taken:

  1. A decision to make a bomb—Iran has not decided to actively build a bomb according to U.S. intelligence
  2. Sufficient quantities of Highly Enriched Uranium (HEU)– Iran has not enriched uranium to weapons grade–90%.  It has enriched uranium to lower levels – 5% and 20%. Any move to enrich uranium above 20% would be detected by inspectors from the International Atomic Energy Agency.
  3. A device – a crude nuclear device would take a year for Iran to build, but this would be a heavy device deliverable by a truck but not Iran’s planes or missiles.
  4. Miniaturizing a warhead – producing a sophisticated nuclear warhead that could be deliverable by missile would take Iran at “another two to three, potentially out to five years,” according to Congressional testimony by General James Cartwright, the then-Vice Chairman of the Joint Chiefs of Staff.
  5. A delivery vehicle – Iran would need to fit the warhead on a ballistic missile and the warhead would have to be sturdy enough to handle re-entry into the atmosphere.  Iran has not demonstrated the capability to build such a vehicle.

(5 steps adapted from “Foreign Policy: How Iran Can Build a Bomb; Cirincioni, Connor July 1, 2010”):

Any move towards building a nuclear bomb would be likely detected by the international community:

  • Secretary of Defense Leon Panetta recently said that if the U.S. detects Iran is moving to develop nuclear weapons, it will have “a little more than a year” to stop them:  “And so, we think we will have the opportunity once we know that they’ve made that decision, take the action necessary to stop [Iran].” (CBS This Morning; September 11, 2012)

Building and testing a weapon would likely require that Iran expel IAEA inspectors who monitor Iran’s uranium production.  Experts believe Iran is unlikely to expel IAEA inspectors and leave the Nonproliferation Treaty any time soon.

  • Arms Control Association: Iran would not likely want to take the dramatic step of breaking out of the nuclear Nonproliferation Treaty (NPT) until it has enough material for several bombs—a point that it will not likely be able to reach for two years or more. Iran would then need time to produce the nuclear device itself (likely several months), which it has never done before, and then develop and probably explosively test a warhead that could fit on a ballistic missile, which would take still more time. (Arms Control Association; August 30, 2012)

The U.S. has assessed, however, that there is one pathway in which Iran would be compelled to expel IAEA inspectors and move forward with building a nuclear weapon.  According to former CIA Director Michael Hayden, when the Bush administration considered a bombing campaign against Iran, “the consensus was that it would guarantee that which we are trying to prevent: an Iran that will spare nothing to build a nuclear weapon and that would build it in secret.”