**The 92% implied probability against the US-Saudi nuclear cooperation agreement (a Section 123 deal) entering into force in 2026 reflects the extended congressional review timeline and mounting bipartisan opposition.** The agreement was signed in July 2026 and transmitted to Congress in late August, triggering the Atomic Energy Act’s 90-day continuous-session review period, which extends into November or later given legislative calendars and recesses. House Democrats introduced a Joint Resolution of Disapproval in mid-September citing inadequate nonproliferation safeguards, including the absence of the IAEA Additional Protocol and a pathway for Saudi uranium enrichment after a joint study. Senators from both parties have requested declassified details on side letters and verification measures. President Trump has tied final implementation to Saudi normalization with Israel via the Abraham Accords, a step Riyadh has not taken. These procedural, verification, and linkage hurdles make completion before year-end highly unlikely under current conditions.