The extent to which Israel’s war against Iran degrades Tehran's nuclear fuel program enough to remove any nuclear weapons optionality is increasingly down to two factors: the uranium enrichment hall buried deep into a mountain at Fordow and the fate of Iran's more than 400 kilograms of uranium enriched to over 60% U-235. That material, alongside centrifuges to further enrich it to weapons-grade 90%-plus, would be crucial for creating the required fissionable feedstock in any Iranian "dash" toward nuclear weapons.