Congressional skepticism and procedural requirements under the Iran Nuclear Agreement Review Act have anchored trader expectations against approval of any final U.S.-Iran agreement in 2026. Following the June 2026 memorandum of understanding that paused hostilities after months of U.S.-Israeli strikes, both chambers passed war powers resolutions directing an end to military action without further authorization, with bipartisan support including several Republicans. Negotiations in the subsequent 60-day window encountered disputes over nuclear inspections, enrichment limits, sanctions relief, and reconstruction funding, with Iranian and U.S. accounts diverging on commitments. Lawmakers from both parties have demanded oversight and votes on any nuclear-related terms, while expressing concerns over enforcement, verification gaps, and the scale of potential economic concessions. With no final deal submitted for review by late September and ongoing partisan divisions over foreign policy authority, the implied probability reflects these structural and political obstacles.