RIYADH, Aug. 16 -- For a year, the central question in US-Saudi negotiations over a civilian nuclear cooperation agreement was not whether Saudi Arabia should have the technology. It was whether the deal could be drafted in language that would make its most dangerous implication disappear.

The implication is uranium enrichment. The path from civilian nuclear energy to a nuclear weapon runs directly through the ability to enrich uranium beyond the levels needed for power generation. Every country that developed nuclear weapons after the first nuclear age has done so through enrichment programs initially described as civilian.

Saudi Arabia's Crown Prince Mohammed bin Salman said years ago, without ambiguity, that if Iran acquired a nuclea...