**The high probability that the US-Saudi 123 nuclear cooperation agreement will not enter into force in 2026 stems primarily from ongoing congressional review and additional political conditions.** Transmitted to Congress in late August 2026, the pact faces a statutory 90-day window during which lawmakers can pass a joint resolution of disapproval, though overriding a potential veto requires supermajorities. Democratic members have introduced such measures, citing the absence of the IAEA Additional Protocol and a pathway allowing future uranium enrichment up to 20 percent after study. A classified US intelligence assessment shared with Congress indicates Riyadh has not ruled out nuclear weapons options, amplifying scrutiny. President Trump has further conditioned implementation on Saudi normalization with Israel via the Abraham Accords, a step Riyadh has shown little willingness to take amid regional tensions. These combined legislative, verification, and diplomatic hurdles make automatic entry into force before year-end improbable under current dynamics.