The term “breakout” is frequently used in discussions about Iran’s nuclear program, but its precise meaning and implications are often unclear or inconsistent. In legal terms, it refers to when an aspiring nuclear weapons state could break out of its commitments under the widely recognized Nuclear Nonproliferation Treaty, which Iran ratified in 1970. (India, Israel, and Pakistan have not joined the NPT; North Korea withdrew in 2003.) In technical terms, breakout refers to when a state achieves nuclear weapons capability as a fait accompli before it can be stopped by diplomatic pressure or military action.

Opinions differ on what constitutes “nuclear weapons capability,” but it is generally accepted as the moment when a country has enough fissile material to make one nuclear device. In Iran’s case the material in question would be U-235, the fissile isotope of natural uranium that can be obtained by various enrichment processes. (Another fissile material is plutonium-239, but Iran’s route to that—irradiating uranium and then reprocessing it—appears to be blocked.)

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Read the rest of the policy analysis at the Washington Institute for Near East Policy.