Iran’s negotiating stalemate over the Strait of Hormuz is not a diplomatic impasse; it is a structural consequence of a Supreme Leader mortgaged to the military. When Mojtaba Khamenei was elevated two months after his father’s death, he inherited a title but not authority. The Islamic Revolutionary Guard Corps selected him because he was pliant, not because he commanded the legitimacy to lead alone. Now, as his government faces the choice between negotiating sanctions relief or blockading global shipping, the IRGC’s hardline faction has veto power over any deal that might constrain Iran’s military deterrence. Escalation is not a reckless gamble; it is the only politically rational choice for a Supreme Leader who rules at the sufferance of his military.

This reshapes what negotiators on all sides should expect in the next 18 months. A deal is possible only if the Trump administration and Israel accommodate the IRGC’s red lines; otherwise, Iran will remain deadlocked on Hormuz and nuclear enrichment indefinitely. The legitimacy crisis at the heart of Iran’s succession is not background noise to the negotiations; it is the determining factor in whether de-escalation is possible at all.

The constitutional vulnerability is stark. Mojtaba, now 56, was not recognized by Iran’s highest religious authorities as a maraji (jurisprudent), the traditional prerequisite for Supreme Leader. His formal credentials rest on dars-e kharej (advanced jurisprudence seminars) that he has taught since 2009, but this lineage is newer and thinner than those of other senior ayatollahs. Iran International notes that “he lacks the scholarly credentials or the theological authority that his father carried for 37 years.” The Assembly of Experts, tasked with selecting the new Supreme Leader, felt the weight of this gap. Eight members boycotted the March 9 vote, citing what they termed heavy pressure from the IRGC. The message was clear; the military had made its preference known, and secular institutions could either accede or be overridden.

The IRGC’s role has evolved from kingmaker to co-ruler. Since March, IRGC commander Ahmad Vahidi has been operating alongside Mojtaba in a de facto military council, according to Washington-based assessments of Iran’s wartime power structure. Mojtaba is sometimes kept in the dark about military decisions being made in his name. One intelligence assessment describes him as agreeing to decisions rather than commanding them, a position markedly weaker than that of his father, who controlled the military apparatus outright. The Supreme Leader’s office has historically been the institution that subordinates all others to its will. For the first time in the Islamic Republic’s history, the IRGC now stands as a parallel power center that can block civilian diplomacy, withhold information from the leader, and effectively veto any agreement that weakens military deterrence.

This explains the impasse on the Strait of Hormuz. Iran’s government, through its chief negotiator Foreign Minister Abbas Araghchi, has proposed a novel offer: reopen the strait to global shipping in exchange for ending the war and lifting the U.S. naval blockade on Iranian ports, while deferring nuclear negotiations to a later phase. The offer is diplomatically sophisticated; it decouples the immediate economic hemorrhage from the unresolved nuclear question. For a pragmatist Supreme Leader, this would be negotiable terrain. But the Trump administration has rejected the formula. Secretary of State Marco Rubio stated that Iran’s terms were unacceptable, and an unnamed U.S. official told the Washington Post that Trump opposed any deal that didn’t simultaneously resolve the nuclear program. The U.S. position is internally coherent; it refuses to allow Iran to gain breathing room on one front while preserving leverage on another.

The civilian negotiators in Mojtaba’s government wanted to accept the trade-off. But the IRGC faction has signaled that yielding the Strait of Hormuz blockade—the regime’s only remaining coercive card—is unthinkable. From the IRGC’s perspective, the blockade demonstrates resolve, deters Israeli or American adventurism in the Persian Gulf, and keeps the U.S. focused on negotiation rather than escalation. Lifting it would undermine the very deterrent that justifies the IRGC’s continued expansion of power within the regime. A Supreme Leader dependent on IRGC patronage cannot overrule that consensus. The negotiation will thus remain stuck; Iran will continue to flex the Hormuz card; the economic toll will mount; and pressure for escalation will build, not ease.

This is the logic that animated the 1989 succession, when Khomeini’s death left Iran without an obvious heir. Ali Khamenei, then president, lacked the maraji credentials that traditionally qualified a leader. The Assembly of Experts elevated him anyway, and the constitution was hastily revised to accommodate the decision. But Khamenei survived as Supreme Leader only by consolidating power through the military; he recruited IRGC commanders into his inner circle, asserted personal control over the armed forces, and made the IRGC into an extension of his will rather than a parallel institution. By the time Khamenei died in February 2026, the dynamic had inverted. The IRGC had grown so large and economically entrenched that it no longer merely served the Supreme Leader; it selected him. Mojtaba is the first hereditary successor in the Islamic Republic’s history, a break with its founding ethos, but his elevation rests on the same military alliance that kept his father in power. The difference is that the IRGC is now confident enough to make this dependence explicit.

Negotiators should prepare for a long stalemate. Iran under Mojtaba cannot de-escalate the Hormuz blockade without undermining the very institution that keeps him in office. The IRGC has no incentive to accept a settlement that constrains its deterrent or its claim to be the regime’s guardian. Civilian diplomacy will be marginalized; military logic will dominate. If the Trump administration insists on nuclear rollback as a condition for sanctions relief, Iran will keep the strait closed. If the U.S. maintains the blockade, Iran will keep retaliatory pressure high. The Supreme Leader will agree to whatever the IRGC decides, legitimizing it with his clerical title. And the negotiation will cycle through iterations of “proposals” that neither side can accept, creating the appearance of diplomatic motion while the underlying power structure—an IRGC-controlled regime in search of a figurehead—remains immobile.