The revelation of an Iranian uranium-enrichment facility buried in a mountain at an Islamic Revolutionary Guards Corps base near the religious city of Qom might seem ominous. If, that is, the Iranians were determined to develop a nuclear weapon. Fortunately, we are advised that they are not. In November 2007, US intelligence agencies wrote a National Intelligence Estimate concluding, “We judge with high confidence that in fall 2003, Tehran halted its nuclear weapons program.” The intelligence community appears to be sticking by its judgment, which means — cue the sighs of relief — that the Qom facility may be only...