The United States has explicitly ruled out returning to the memorandum of understanding reached with Iran in June, a stance that has effectively chilled multilateral diplomatic efforts to revive the process this week. Following the announcement, risk-aversion sentiment in financial markets surged, pushing Brent crude prices briefly above $88 a barrel, while major global stock indices came under broad downward pressure.

Previously, this preliminary agreement, signed by senior US officials and brokered through multilateral mediation, was expected to facilitate the reopening of the Strait of Hormuz, advance negotiations on Iran's nuclear program, and quell regional conflicts. Under the original framework, the US was to consider easing sanctions on Iran and unfreezing certain overseas assets. However, the deal quickly unraveled after Iran subsequently attacked vessels to assert its control over the critical waterway. The US has since pivoted to a strategy of severe economic pressure, especially given that the memorandum was already highly controversial domestically for being perceived as overly concessional to Iran.

In response to the tough US posture, Iran has shown no signs of yielding. Senior officials from the Islamic Revolutionary Guard Corps stated via state media that Iran will only reopen the Strait of Hormuz if the US ceases its obstruction and returns to the original memorandum framework, insisting that its predefined conditions must be accepted. Conservatives in Tehran have even pointed out that the relevant clauses of the original agreement effectively grant Iran the right to dictate the strait's passage conditions, a claim to which the US has yet to publicly respond.

The diplomatic stalemate has rendered the intensive shuttle diplomacy of the past week largely fruitless. A visit by senior Pakistani military officials to Tehran yielded no substantial progress. Subsequently, Oman's foreign minister attempted to push forward a transit corridor agreement as a foundation for broader negotiations on opening the strait, but the effort stalled as Iran insisted on amending the deal to secure greater control over shipping lanes. Notably, while Iranian officials claimed a consensus on shipping routes had been reached during talks in Oman, Omani authorities did not confirm this, and Iranian officials themselves offered contradictory accounts of the negotiation details. Furthermore, a meeting in Tehran between Qatar's foreign minister and his Iranian counterpart merely focused on exploring ways to prevent further escalation, failing to deliver any breakthroughs. Analysts note that the original memorandum of understanding has effectively collapsed, significantly increasing the difficulty for mediators to broker a compromise between the two sides amid the current complex landscape.