Stalled bilateral negotiations represent the dominant factor behind the elevated probability that no UN Security Council resolution will endorse a final U.S.-Iran agreement by year-end. A June 2026 memorandum outlined a 60-day path to finalize terms, including a binding UNSC endorsement, yet indirect talks via intermediaries have since faltered over nuclear enrichment levels, with Washington seeking meaningful curbs and Tehran defending its NPT rights. Recent UNSC clashes, including Russian and Chinese vetoes of sanctions-monitoring extensions and disputes over expired Resolution 2231, underscore persistent P5 divisions. Proposals on maritime access and sanctions relief remain unresolved, with officials on both sides noting insufficient progress and missed opportunities amid ongoing regional tensions. These dynamics leave insufficient time for the required diplomatic alignment and procedural steps before the deadline.