Iran and US Explore Unprecedented Signing Mechanism for Nuclear Deal as Tehran Issues Stark Warning

The United States is attempting to close a nuclear agreement with a counterparty it cannot see, cannot contact directly, and has designated for sanctions. Iran's Supreme Leader Mojtaba Khamenei has been underground for nearly three months, communicating with his own negotiators through courier networks that introduce days-long delays into each round of talks [1]. Simultaneously, Iran's president has invoked the language of the Iran-Iraq War — mass sacrifice, civilian resistance, national mobilization — casting the current confrontation as an existential struggle rather than a managed diplomatic crisis [2].

The result is a negotiation unlike anything in the history of arms control: a deal that may ultimately be signed by a man the U.S. Treasury designated in 2019 for acting on behalf of his father's "destabilizing regional ambitions," delivered through intermediaries to a government that officially labels him a military target [3][4].

The Courier Mechanism: How It Works and Why It Matters

Mojtaba Khamenei became Iran's third Supreme Leader on March 8, 2026, following the death of his father Ali Khamenei in a strike on February 28 [5]. He went underground immediately — by design, even senior Iranian officials do not know his location and cannot contact him directly [1].

Iranian negotiators have been given broad parameters by the Supreme Leader on which issues they can discuss, but updating that guidance in real time is functionally impossible. When the U.S. sends proposed deal language, it passes through intermediaries before reaching Khamenei, and responses arrive days later [1]. Secretary of State Marco Rubio has acknowledged the delays publicly, noting "it takes the Iranians — takes them a little while longer to get back" [6].

Dr. Omar Mohammed, a counterterrorism analyst, has described this as "courier latency" — a structural constraint on diplomacy where "messages are moving by courier, and responses are arriving days late." He characterizes the resulting arrangement as one where any agreement "will have to be designed for a permanently invisible counterparty whose enforcement depends on his continued survival. That is not arms control as it has been conventionally understood" [1].

The Times of Israel reported the situation has been compared to "a sitcom" by one Western diplomat involved in the talks, given the elaborate bunker networks and courier chains that slow every exchange [7].

The Sanctions Designation Problem

Mojtaba Khamenei was designated by OFAC on November 4, 2019 — the 40th anniversary of the Iran hostage crisis — under Executive Order 13876. The Treasury Department stated he was designated "for having acted or purported to act for or on behalf of, directly or indirectly, the Supreme Leader of Iran," coordinating with IRGC commanders and the Basij paramilitary force [3][8].

That designation has not been lifted. Under U.S. sanctions law, it is generally prohibited for any U.S. person to engage in transactions with a Specially Designated National (SDN). The executive branch has the authority to issue specific licenses or general waivers through OFAC to permit otherwise prohibited dealings, but no such waiver has been publicly announced for negotiations with Khamenei [3].

The Trump administration has not publicly addressed the legal mechanism by which it intends to formalize an agreement signed by a designated individual. The 2015 JCPOA was structured as a political commitment rather than a binding treaty and did not require Senate ratification, but it was negotiated with officials who were not under individual U.S. sanctions at the time. The courier arrangement adds a further layer of legal ambiguity: it is unclear whether a document physically signed by Khamenei in hiding and delivered by intermediaries constitutes a valid executive agreement under domestic or international law.

What Is on the Table

As of late May 2026, U.S. and Iranian negotiators have agreed on "broad principles" but no final text [6]. The proposed framework centers on several pillars:

Nuclear provisions: Iran would dispose of its enriched uranium stockpile. The mechanism for disposal — whether shipment abroad, dilution, or conversion — remains under negotiation. A senior U.S. official told Al Jazeera the disagreement is over "how" rather than "whether" disposal happens [6]. President Trump has stated the deal would ensure Iran "can never possess a nuclear weapon" and has emphasized it represents "the exact opposite" of the 2015 JCPOA [9].

Strait of Hormuz: Both sides have discussed reopening the strategic waterway. Trump said the Hormuz component was "largely negotiated" [9]. Iran's Tasnim news agency reported vessel traffic would return to pre-war levels within weeks, with the U.S. naval blockade lifted within 30 days [6]. Iranian media insist the strait would remain "under Iranian supervision" [9].

Sanctions relief: Iran is demanding the unfreezing of blocked assets, with partial release in the initial phase. The U.S. has reportedly pulled back from earlier proposals on this point [6].

Timeline: The framework gives both parties 60 days to reach final deal points after an initial memorandum of understanding is signed [6].

Comparing the Numbers: This Deal vs. the JCPOA

The 2015 JCPOA set specific, verifiable limits on Iran's nuclear program: enrichment capped at 3.67%, a stockpile limit of 202 kilograms of low-enriched uranium, and operation of only 5,060 IR-1 centrifuges at Natanz [10][11]. Iran accepted the most intrusive inspection regime ever negotiated, including continuous IAEA monitoring of its entire fuel cycle and implementation of the Additional Protocol [10].

The current proposal's precise technical parameters have not been made public. What is known: Iran would relinquish its enriched uranium stockpile entirely, and a "significant time-limited negotiation on nuclear matters" would follow, according to Rubio [9]. Unlike the JCPOA, which contained sunset clauses allowing restrictions to expire between 2026 and 2031, the Trump administration claims its deal would impose permanent prohibitions [9].

The verification question is particularly acute. Iran suspended IAEA Additional Protocol access in February 2021 and terminated all remaining IAEA access on February 28, 2026 [12]. Surveillance cameras have been disabled and seals removed from all declared facilities. The IAEA cannot currently verify the status of enriched material stockpiles or whether covert enrichment activities continue [12].

Iran's Nuclear Program: Where Things Stand

Iran's stockpile of 60%-enriched uranium — the highest level produced by any non-weapons state — reached 440.9 kilograms as of May 2026, according to IAEA Director General Rafael Grossi [12]. That quantity is theoretically sufficient for approximately 10 nuclear weapons if further enriched to 90% weapons-grade [12].

Source: IAEA Quarterly Reports

Data as of May 24, 2026CSV

The growth trajectory is striking. Iran held zero 60%-enriched uranium when the JCPOA collapsed in 2018. It began producing at that level in April 2021, initially accumulating slowly — 2.4 kg by early 2021 — before accelerating sharply. By late 2024, the stockpile had reached 182.3 kg. It nearly doubled over the following year [12].

Breakout time — the period needed to produce enough weapons-grade material for a single device — is estimated at two to four weeks using existing 60%-enriched feedstock and surviving centrifuges at the Fordow facility, which is buried deep in a mountain [12][13]. Before the JCPOA collapsed, breakout time was estimated at approximately one year [10].

Israel's Operation Epic Fury strikes between June 13–24, 2025, damaged several Iranian nuclear facilities but did not eliminate the program [12]. Analysts at the Bulletin of the Atomic Scientists assessed that Iran likely transferred highly enriched uranium to Isfahan before the strikes [14].

The 'Mass Sacrifice' Warning

On May 24, 2026 — the anniversary of Iran's 1982 recapture of Khorramshahr from Iraqi forces — President Masoud Pezeshkian delivered remarks invoking Iran's foundational wartime mythology. "Khorramshahr today is Iran, the Persian Gulf, and the Strait of Hormuz," he stated [2].

The Battle of Khorramshahr was one of the bloodiest engagements of the Iran-Iraq War (1980–1988). Iraqi forces under Saddam Hussein captured the southwestern city early in the conflict; Iranian forces retook it after months of urban combat that cost thousands of lives. The city is known in Iranian public memory as the "City of Blood" [2].

Dr. Mohammed assessed Pezeshkian's rhetoric as mapping "the 1980–82 defensive-war frame onto the current confrontation," casting Iranian citizens as expected to "stand and fight" with "resistance, sacrifice, repelling aggression" as cultural defaults. He characterized the signal as indicating "existential war, not a managed crisis" [2].

Iran held live-fire drills in the Strait of Hormuz while a U.S. armada remained in the region [2]. Western analysts have identified several escalation options Tehran could pursue if talks collapse: continued closure of the Strait of Hormuz (through which roughly 20% of the world's oil passes), expanded drone and missile operations, and activation of regional proxy networks including groups in Iraq, Lebanon, and Yemen [2][6].

Domestic Opposition on Both Sides

Iran

The power vacuum created by the elder Khamenei's death and Mojtaba's disappearance underground has emboldened hardliners [15]. Within the IRGC, Abdollah Haji-Sadeghi, the Supreme Leader's representative to the Corps, declared: "There are no negotiations for now. We will negotiate whenever the enemy accepts our conditions" [16].

In the Majlis (parliament), the National Security and Foreign Policy Committee has publicly questioned the value of remaining in the Nuclear Non-Proliferation Treaty. Spokesman Ebrahim Rezaei said lawmakers had discussed preserving Iran's nuclear "achievements," while MP Vahid Ahmadi stated that enriched materials would "under no circumstances" be removed from the country [16]. Some hardline figures are now openly arguing Iran should pursue nuclear weapons capability as a deterrent [15].

The IRGC-affiliated Tasnim News Agency has suggested that U.S. proposals for back-channel talks are designed to divide Iran's political establishment [16].

United States

Congressional opposition spans both parties but centers on procedural and substantive objections. Republican Senator Thom Tillis predicted the deal is "doomed to fail" because it lacks congressional oversight [17]. Any agreement related to Iran's nuclear program would trigger review requirements under the 2015 Iran Nuclear Agreement Review Act (INARA), which gives Congress 30 to 60 days to review and potentially block implementation [17].

Since March 2026, Congress has voted on nine War Powers Resolution measures related to Iran hostilities, rejecting all of them [17]. The Foundation for Defense of Democracies (FDD), a Washington think tank with significant influence on the administration's Iran policy, has pushed for a harder line, arguing that sanctions relief would fund proxy operations and that any deal with sunset provisions merely delays Iran's path to a weapon [18][19].

The Economic Pressure Behind the Talks

Iran's economic crisis provides the backdrop — and arguably the primary motivation — for Tehran's willingness to negotiate at all. The numbers are severe.

Source: World Bank Open Data

Data as of Dec 31, 2024CSV

Official inflation stood at 32.5% in 2024 according to World Bank data, but by early 2026 the picture had worsened considerably. Food inflation reached 105% year-on-year by February 2026, up from 64% in October 2025 [20]. Prices rose roughly 40% in the six weeks following the outbreak of direct hostilities [20].

Source: Bonbast / Open Market

Data as of May 1, 2026CSV

The Iranian rial has collapsed from approximately 42,000 per dollar in 2017 to over 1.3 million by early 2026 on the unofficial market — a depreciation of more than 96% [21]. The rial lost 60% of its value in the months following the June 2025 Israeli strikes alone [20]. The central bank issued its largest-ever currency denomination, a 10 million rial note, as authorities struggled to make payroll [20].

Source: World Bank Open Data

Data as of Dec 31, 2025CSV

Official unemployment stood at roughly 8.3% nationally, but youth unemployment (ages 15–24) reached 21.2% in winter 2025–26, with young women facing a rate of 34.9% [22]. Destroyed factories, energy facilities, and infrastructure have left many more effectively jobless beyond what official statistics capture [20]. An Iranian official warned the country "will face a disaster" without sanctions relief, as major industrial plants need months or years to repair [20].

The question of who benefits from sanctions relief is central. Critics, including the FDD, argue that IRGC-linked enterprises control large segments of Iran's economy, and that freed-up revenue would flow disproportionately to the state and military apparatus rather than ordinary citizens [18]. Iran's oil export revenue alone was estimated at a minimum of $30 billion annually before the current conflict [20].

The Skeptics' Case: Why a Deal Could Make Things Worse

The Foundation for Defense of Democracies and allied critics have articulated several specific objections [18][19]:

Sunset clauses: Even if this deal claims to impose permanent prohibitions, skeptics point to the JCPOA experience, where restrictions were scheduled to expire between 2026 and 2031, as evidence that time-limited provisions ultimately give Iran a pathway to nuclear capability. The key question is whether "permanent" commitments made through an informal executive arrangement carry more weight than the JCPOA's specific, negotiated timelines [10][18].

Cash-flow effect: Sanctions relief, critics argue, would provide billions in revenue that Iran would channel to Hezbollah, Hamas, Palestinian Islamic Jihad, and Shia militias in Iraq. The FDD has testified to Congress that reintegration into the SWIFT financial system would make it far harder to track and interdict these flows [18].

The courier precedent: Perhaps the most novel objection: formalizing a deal signed by a sanctioned individual through intermediaries effectively normalizes the circumvention of terrorism-related designations. If Mojtaba Khamenei can be a counterparty to a major international agreement while remaining on the SDN list, critics ask what the designation means in practice [1][3].

Defenders of engagement counter that the alternative — no deal — leaves Iran with a growing enriched uranium stockpile, no international inspections, and continued regional instability. The Arms Control Association has emphasized that returning to any form of verified limits is preferable to the current situation, where the IAEA has no access and breakout time has shrunk from a year to weeks [11][12].

Enforcement Without a Treaty

The proposed agreement would not be a treaty subject to Senate ratification. The administration has indicated it would rely on executive agreement authority, as the Obama administration did with the JCPOA [17].

The original JCPOA's snapback mechanism — which allowed UN sanctions to be reimposed without a Security Council veto — was activated in August 2025 by France, Germany, and the United Kingdom. UN sanctions were officially reimposed on September 27, 2025 [23]. But China and Russia have challenged the activation's legality, arguing that the E3 nations lost standing to invoke it by failing to meet their own JCPOA obligations [23].

This dispute raises a direct question about any new deal's enforcement architecture. If a new snapback mechanism is included, its effectiveness depends on multilateral cooperation that is currently fractured. Russia has called the E3's invocation "null and void" [23]. China has supported that position. Without their compliance, enforcement becomes largely a unilateral U.S. action — exactly the kind of maximum-pressure approach that preceded the current conflict.

The Iran Nuclear Agreement Review Act remains law, giving Congress a procedural lever to block implementation of any new nuclear agreement [17]. Whether the administration will submit this deal for review, or argue it falls outside INARA's scope because it is structured differently from the JCPOA, is an unresolved legal question.

What Comes Next

The 60-day window for final terms has not yet begun because no memorandum of understanding has been signed [6]. The courier mechanism means even the signing itself could take days or weeks once terms are agreed. Rubio has described the situation as "a pretty solid thing on the table" regarding the Strait of Hormuz, with nuclear issues entering "a real significant time-limited negotiation" [9].

Tehran's position is that it will not sign unless all clauses are "fully agreed and guaranteed," and Tasnim has warned the agreement "may be canceled" if what it calls U.S. obstruction continues [6]. Iran's hardliners are pushing in the opposite direction — toward open nuclear weapons capability and rejection of any engagement with Washington [15][16].

The fundamental tension is structural. The U.S. is trying to negotiate the most consequential arms control agreement in a generation with a leader who is simultaneously a designated sanctions target, a designated military target, and physically unreachable. Whether the resulting arrangement can produce a deal that is legally binding, technically verifiable, and politically durable on both sides remains the central unanswered question.