The US-Saudi 123 nuclear cooperation agreement, signed in July 2026 and transmitted to Congress in late August, remains subject to a statutory 90-day review period that extends into late fall. Traders assign a 90% probability against entry into force this year due to active congressional opposition, including from Democrats and nonproliferation advocates concerned over the enrichment pathway and limited IAEA Additional Protocol commitments. President Trump has publicly conditioned advancement on Saudi Arabia joining the Abraham Accords, a step Riyadh has tied to progress on Palestinian statehood. Parallel bilateral safeguards negotiations in Vienna and the need for IAEA Board of Governors approval add further procedural delays, while classified side letters limit transparency. These overlapping legislative, diplomatic, and institutional requirements make completion before year-end unlikely under current timelines.