War Diary Day 23: US ultimatum pushes war to the brink

On the 23rd day of the US- Israeli war against Iran, the conflict entered its most dangerous phase yet as US President Donald Trump’s 48-hour ultimatum imposed a hard deadline on an already grinding and multi-front war. The demand that Iran fully reopen the Strait of Hormuz or face strikes on its power infrastructure has compressed timelines and raised the risk of immediate escalation.

Tehran’s response was swift. It warned that any attack on its power, fuel or energy infrastructure would trigger strikes not only on US and Israeli-linked assets, but also on critical energy, IT and desalination facilities across the Gulf. This explicit warning, backed by proven Iranian capability to deliver on their warnings, sharply raised the stakes, particularly for Gulf states. At the operational level, US and Israeli strikes have continued against Iranian coastal missile sites and access tunnels near Kharg and the Tunb islands. These actions look to be designed by the US and Israel to degrade Iran’s ability to control the Strait before the alliance commits to a full-scale ground operation. Yet Iran has retained the operational control of the Strait by keeping it selectively open, allowing limited passage for ‘friendly’ countries while restricting coalition-linked traffic. And simultaneously, Tehran has continued to load and export oil. This indicates that Iran is sustaining economic pressure without fully closing off its own options. The US military posture, meanwhile, has shifted toward a more forward and ready stance. The USS Tripoli and its embarked Marine force, now having entered Centcom’s Area of Responsibility, are now fully operational, conducting escort and surveillance missions and have thus expanded the range of options available to Washington, including potential operations against strategic islands.

This has been accompanied by a notable expansion of coalition support, with several Western and allied countries committing naval assets after weeks of hesitation. While this development signals a hardening of positions, it also introduces new vulnerabilities as well. The risks attached to the ultimatum are widely understood. Striking Iran’s power grid is unlikely to produce Tehran’s rapid capitulation, given the dispersed nature of Iranian plants. In contrast, retaliation against more concentrated infrastructure across the Gulf and in Israel could have immediate and severe consequences. Gulf desalination facilities, energy installations and supply chains are highly exposed, therefore any Iranian retaliation would lead to power outages, water shortages and wider economic disruption. Stress is already visible in energy markets, with prices and insurance costs continuing to rise. What the new phase holds will be seen shortly. At the same time, Iran has shown no indication of economic strangulation. Its continued exports through Hormuz, combined with rejection of external proposals to increase supply under the conditional US offer of ending curbs on oil exports, suggests that Tehran has enough room to manoeuvre. On the battlefield, the conflict continued to intensify across multiple fronts. Iran launched another wave of missile strikes, including impacts near sensitive Israeli locations like Dimona and Arad, which reinforced both the operational and psychological dimensions of the war. Claims of more engagements against advanced US and Israeli aircraft — F-15 and F-16 — are being amplified domestically in Iran, building on the earlier successful hit on an F-35 stealth jet. This messaging is contributing to a narrative of resilience.

In Lebanon, the tempo of fighting has increased, with Hezbollah expanding operations and hitting Israeli forces, which in military terms is called behind the ‘enemy lines’. Israel is, meanwhile, attempting to sever access routes south of the Litani River. As of now, the Israeli strategy, rather than isolating the battlefield, has turned border areas into sustained zones of attrition, with limited territorial change but rising costs. Meanwhile, in Iraq, the activity of Iran-aligned militia continues to pressure US positions, whereas in Yemen, the Houthis remain on high alert, with indications that any move to forcibly reopen the Strait could trigger action in the Red Sea, linking the two maritime theatres. In a related development, the hardening of the tone of Ayatollah Sistani’s camp, as evidenced from Eid sermons in Karbala and Kazimiya, suggests rising concern there about the aggravating situation. Beyond these fronts, tensions have also escalated in the Palestinian territories, where Israeli settler violence in the West Bank on Saturday night, which is being described by Israelis as a “Night of Fire”, risks opening another axis of instability. This widening of pressure points tells how the conflict is no longer contained and is instead spreading across interconnected theatres. Diplomatically, the space for de-escalation has narrowed further with Trump deliberating elimination potential off-ramps to achieve something he can show as concrete success. Leaks from Washington, in parallel, suggest that the US is looking for interlocutors in Tehran, but the real issue is its own credibility, having waged war against Iran twice while negotiations were continuing. Public sentiment is showing visible strain in the Arab streets as well as in Israel. In Israel, war fatigue has begun to take its toll, with informal polling and reservist sentiment suggesting that support for the war was slipping rapidly. Across the Arab world, reactions remain mixed but increasingly charged. Protests in the Levant, Iraq and Yemen have framed Trump’s ultimatum as economic coercion, while in the Gulf, public sentiment is reflecting a combination of anger at Iranian strikes and anxiety over the prospect of wider disruption.

Egypt was particularly in focus for the past couple of days, where a widely circulated Eid sermon has added to the debate across the Arab countries, with its messaging interpreted by some as a call for separation from those on the side of Israel. By the end of Day 23, the conflict stands on a razor’s edge. The 48-hour clock has transformed the conflict into a high-risk gamble, with both sides preparing for the consequences of the next move. Whether the deadline produces a breakthrough or triggers a wider regional crisis will likely become clear in a day or two.