US-Iran nuclear deal?

rationale:

The probabilities are driven by the June 17-19 signing of a 14-point US-Iran memorandum of understanding (MOU) that established a 60-day window to negotiate a comprehensive nuclear deal. Crucially, the MOU itself does not qualify as a deal under the strict criteria, as it merely maintains the nuclear status quo and defers concrete restrictions on enrichment and stockpile disposition to a later mechanism axios.com, axios.com, reuters.com. The timeline, substantive hurdles, and regional dynamics shape the probability curve through the rest of 2026.

Timeline and the 60-Day Window The 60-day negotiation window formally began around June 18 and concludes in mid-August reuters.com. Because the parties are aiming for this deadline, a resolution 'Before August' (4%) is highly unlikely, as it requires finishing well ahead of schedule when initial talks have barely begun. The notable jump to 'Before September' (21%) captures the potential for an on-schedule conclusion of the final deal around mid-August.

Core Obstacles and Strict Verification Criteria To qualify, a final agreement must include 'concrete, objectively ascertainable' and 'verifiable' restrictions on Iran's nuclear program. The substantive gap here is severe. The US demands zero enrichment and the removal or destruction of enriched uranium stockpiles reuters.com. Conversely, Iran seeks 'reversible zero enrichment'—a temporary suspension while retaining NPT rights and diluting domestically rather than exporting material time.com. Because the MOU granted Iran immediate oil-sanction waivers axios.com, Tehran has already secured early economic relief. This reduces its urgency to concede on these hardest issues and increases the risk of prolonged delays or stalling.

Geopolitical Risks and Momentum Progress faces significant external risks. Planned talks in Switzerland were already postponed amid fighting in Lebanon, highlighting how regional spillover can easily derail the schedule reuters.com, apnews.com.

However, there is genuine process momentum that keeps year-end probabilities in the mid-40s (Before 2027: 46%). Both sides have strong incentives to reach a comprehensive agreement: Iran faces a severe economic crisis, while the US administration wants a major diplomatic and legacy victory. Furthermore, Iran's Supreme Leader authorized the MOU despite reservations reuters.com, the IAEA indicates technical work on concrete steps can begin , and there are reports of auxiliary proposals showing some mutual understanding on uranium enrichment cnn.com.

Conclusion The probabilities steadily increase through the fall as potential extensions to the 60-day window are priced in ('Before October' at 28%, climbing to 'Before December' at 40%). However, the strict requirement for verifiable nuclear restrictions, the massive gap on stockpile disposition, and the risk of talks stalling due to early sanctions relief and regional conflict keep the ultimate year-end probability slightly below even odds at 46%.