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A Creaky Floor For U.S.-Iran Diplomacy

Jun 15, 2026 | International Crisis Group

The memorandum of understanding announced by the United States and Iran on 14 June is a positive, albeit preliminary and precarious, development. Coming more than three and a half months after the U.S. and Israel attacked Iran on 28 February, and after weeks of negotiations during a ceasefire that often seemed unworthy of the name, the memorandum is a welcome step toward ending a misbegotten war that caused enormous damage to countries across the Middle East and beyond – as well as toward establishing parameters for further diplomacy.

Yawning gaps remain between their respective positions, and a fuller accord is far from guaranteed. But history argues for taking negotiations more seriously this time round, not less.

A war that the U.S. and Israel began without offering any credible legal justification and amid seemingly productive negotiations between Washington and Tehran is now ending equally strangely – with the announcement of a deal that is to be signed only on 19 June and whose contents remain confidential. Still, based on preliminary reports , the memorandum, concluded by Washington and Tehran with the help of mediating parties – including Pakistan, Qatar, Egypt, Türkiye, Saudi Arabia and Oman – will serve two immediate purposes. First, it will extend and put a floor beneath the shaky truce that took effect on 8 April. That arrangement quelled major hostilities, but left room for significant U.S.-Iranian military exchanges, Iranian fire at Gulf Arab states, a flare-up between Iran and Israel centred around Lebanon, and the spectre of still more hazardous escalation. Perhaps most importantly, it also left maritime traffic through the Strait of Hormuz largely halted, owing to Iranian strikes on shipping and a subsequent U.S. dragnet aimed at Iran-linked vessels, roiling the global economy and jacking up energy and food prices. Rolling back these duelling blockades and restoring commerce through the waterway is supposed to be the agreement’s first deliverable, alongside steps to lower tensions among the U.S., Iran and their respective partners.

Secondly, the memorandum will give U.S. and Iranian negotiators 60 days to work toward a more detailed accord – something that eluded them over multiple rounds before the twelve-day war in June 2025 and again before the war that one may hope has just ended. The core issues are well known: how to resume international inspections of Iranian nuclear facilities; what to do with fissile material produced before June 2025; what limits should apply to a program now approaching a year of opacity at key sites; and what degree of economic relief Iran will receive in return.

That Washington and Tehran were able to agree to such a sequence – an initial proof of concept regarding their respective willingness to honour a deal, followed by a return to talks about the most stubborn points of contention – is no small achievement. It underscores that the two adversaries learned at least one important lesson from the conflict and the failures of recent talks: the blockade and counter-blockade that played out in the Strait of Hormuz and the Gulf proved a double-edged sword that allowed each party to hurt the other but ensured that both would be harmed in return. The memorandum will curb these tactics and thus represents a step away from lose-lose dynamics. It also will allow both the U.S. and Iran to claim a measure of victory: Washington likely will insist that the memorandum reopens the strait to unimpeded traffic, returning to the pre-war status quo, while Iran will claim that it retains control of a waterway it can close at will. In short, the agreement implicitly recognises that neither side was able to deliver a knock-out blow, but that both have sufficient capacity to impose significant costs on the other.

Judgment as to the sustainability of the memorandum itself should be reserved until more information is available about its contents.

Judgment as to the sustainability of the memorandum itself should be reserved until more information is available about its contents – and here questions abound. These include how it addresses the gap between the Islamic Republic’s desire to defer nuclear deliberations and the White House’s need to have basic parameters committed to paper; whether and to what extent it provides immediate economic relief for Iran; whether it tackles modalities of managing the Strait of Hormuz; and, of course, whether both sides have the same interpretation of the above. One issue in particular – the linkage with Israel’s presence in Lebanon and the fighting there between the Israeli army and Hizbollah – is almost certain to put the understanding to an early test. In the lead-up to the memorandum and on the very day it was announced, there have been ample warning signs. Iran has made clear that the deal requires a cessation of Israeli attacks in Lebanon; the Israeli government appears to want a free hand; and the U.S. has variously taken a back seat and stepped in vigorously to stop hostilities from snowballing further, including through the use of choice words to rein in Prime Minister Benjamin Netanyahu, the most ardent opponent of a bargain with Iran. The bottom line is that any escalation in Lebanon is liable to put the U.S.-Iranian agreement at risk. Washington will need to use its leverage to prevent this scenario.

Reaching the memorandum of understanding was hard enough, given the level of mutual mistrust – compounded on the Iranian side by having twice been attacked by the U.S. amid negotiations – and the distinctive decision-making obstacles both sides face: an historically opaque Iranian system profoundly disrupted by the killing of many of its leaders early in the war, as well as the constant fear of further strikes, and a U.S. system under the thumb of an unprecedentedly unpredictable, erratic president. Under these circumstances, it will be far more daunting still to achieve a detailed agreement. The two sides could make a preliminary deal because both could cast themselves as being in a position of strength, the U.S. due to its overwhelming might and the damage it did to Iran’s military and economic assets, and Iran because it stood fast and exacted huge tolls on the U.S. and world economies. This same dynamic is likely to hamper achievement of a fleshed-out accord, for neither side will be inclined to make big compromises.

Past nuclear negotiations, including both successes and failures, provide good reason for scepticism that the detailed non-proliferation and sanctions relief provisions of a fuller agreement can be completed, let alone in just two months. The well-charted terrain, together with the demonstrated costs of renewed hostilities, arguably will help sharpen the focus needed to finish the job. If, as some reports suggest , Iran has agreed in principle to a years-long, verified moratorium on uranium enrichment, so long as this condition does not negate its asserted nuclear rights, proliferation risks could be minimal. Likewise, Iran allegedly has indicated willingness to dispose of its stockpile of enriched fissile material. As for sanctions relief, in the past Trump has mused about the possibility of providing Iran with substantial economic benefits, including by loosening the U.S. primary embargo and setting up a significant recovery fund. Such an arrangement could give Iran an incentive to agree to substantial nuclear concessions.

But a full-fledged settlement is nowhere close to guaranteed. The two sides’ positions are very likely far apart on almost every significant issue: the number of years of a putative enrichment moratorium; what Iran will be permitted to do at its expiration; the mode of disposal of Iran’s enriched uranium and how to guarantee that all has been unearthed; the intrusiveness of International Atomic Energy Agency inspections and how they might overcome years without adequate monitoring or verification of Iran’s nuclear program to ensure there is no clandestine effort; the scope of sanctions and other economic relief; the status of the Strait of Hormuz; and, importantly, the sequencing, as Iran will seek tangible dividends up front, due to its mistrust of Washington, while the U.S. will be wary of frontloading rewards. The Trump administration will need to negotiate patiently and draw on technical expertise, neither of which it has proven particularly adept at doing so far, and there is reason to doubt the new Iranian leadership’s appetite for far-reaching compromise. Both leaderships also will face internal (and, in the Trump administration’s case, Israeli) backlash against a memorandum that failed to meet maximalist objectives, further narrowing their respective room for manoeuvre. President Donald Trump’s eagerness to demonstrate that he has improved upon the terms of the 2015 Joint Comprehensive Plan of Action negotiated under President Barack Obama, which he tore up during his first term and has continuously derided, creates additional political pressure.

Trump has been very clear that the U.S. still has its finger on the trigger.

Indeed, it is not difficult to envision alternatives to the conclusion of a more comprehensive agreement in which the 60-day timeframe spills over into a longer, inconclusive process. One such scenario is a return to full-scale conflict that undoes what has thus far been achieved; the internal and regional dynamics could very well push in this dangerous direction. Trump has been very clear that the U.S. still has its finger on the trigger. He has also been extremely unsettling in describing the potential targets he has in mind.

Another possible tableau is that, having secured enough through the memorandum of understanding to construct their respective victory narratives, both sides would be content to live for a longer time with a tenuous new status quo that leaves key questions unresolved. The Strait of Hormuz would be open, albeit always at risk of renewed hostilities and thus unlikely to return to pre-war traffic volumes. Washington would seek to deter any resumption by Iran of its nuclear efforts with the threat of military strikes but would have to contend with a program that is not subject to agreed-upon constraints. Tehran would enjoy the economic benefits provided for in the memorandum, but not the broader sanctions relief it desperately needs to begin to recover, rebuild and respond to the Iranian people’s needs. Such an outcome would, by definition, be unsatisfactory, unstable and perilous. If the other option is renewed hostilities, accepting the imperfections of the memorandum would nonetheless be far preferable.

Regardless of the memorandum’s contents, the war’s ambiguous end carries a clear lesson: wars of choice, launched based on inflated threats and wishful thinking, are far more likely to deepen than to solve the problems they purport to address. The specific lesson regarding Iran is also difficult to escape. After years of deploying every available coercive tool, from suffocating sanctions to military force, diplomacy remains the only approach that has delivered positive results. That reality argues for taking it more seriously this time round, not less.