**Congressional approval of a comprehensive Iran nuclear agreement remains unlikely in 2026 due to entrenched partisan divisions, Senate Republican demands for stringent conditions, and the shift toward limited interim arrangements.** Recent developments center on the June 2026 memorandum of understanding signed by the Trump administration to pause hostilities and address Strait of Hormuz shipping, which the White House forwarded to Congress under the Iran Nuclear Agreement Review Act framework. Lawmakers from both parties expressed frustration over limited briefings, while Republican senators including Lindsey Graham and Tom Cotton publicly conditioned any durable pact on full Iranian dismantlement of enrichment capabilities, missile programs, and terrorism support—standards that exceed the interim terms under discussion. House and Senate war-powers resolutions in June and July further signaled congressional assertiveness, passing with bipartisan support to curb unilateral executive action. As of early August, ongoing talks mediated by Oman focus narrowly on reopening shipping lanes rather than a full nuclear accord, with Vice President JD Vance noting the process would be “messy” and time-consuming. Iran has also denied direct U.S. negotiations at points, reinforcing the gap between executive diplomacy and the legislative threshold for sanctions relief or a binding agreement. These factors sustain trader expectations that no approvable deal will clear both chambers before year-end.