The United States and Iran have entered a dangerous new phase of open military confrontation, with American forces carrying out strikes along Iran's southern coastline for a fourth consecutive day and Tehran responding with attacks on US bases across the Gulf. President Donald Trump has threatened to expand the campaign next week to target Iran's power plants and bridges unless Tehran agrees to negotiate, raising urgent questions about the legality and consequences of the conflict — and whether any diplomatic path remains.

At the heart of the dispute is the Strait of Hormuz, the narrow chokepoint between the Persian Gulf and the Arabian Sea through which roughly one-fifth of the world's oil and liquefied natural gas passes during peacetime. US Central Command says its strikes are aimed at degrading Iranian capabilities used to attack commercial shipping in the strait. Iranian state media reported explosions near the port city of Bandar Abbas and on the Gulf island of Qeshm. In response, Iran's Islamic Revolutionary Guard Corps (IRGC) struck what it described as command-and-control and logistics facilities of the US Fifth Fleet in Bahrain, while Iran also launched drone attacks on a military base in Jordan hosting American warplanes. Jordan's military said it intercepted and shot down three ballistic missiles that entered its airspace, and Kuwait also came under attack. The IRGC warned that if Washington sought to control regional maritime routes, energy exports would be "for everyone or for no one."

The current confrontation is rooted in the collapse of a fragile ceasefire. A 14-point memorandum of understanding signed in Islamabad on 17 June had halted six weeks of fighting that began when US and Israeli forces struck Iranian targets on 28 February — a campaign that included the killing of Supreme Leader Ayatollah Ali Khamenei. The agreement called for a 60-day ceasefire and the reopening of the strait to commercial shipping, but its language was ambiguous on key issues including Iran's nuclear programme and reconstruction payments. The ceasefire unravelled late last week after Iran fired on ships it deemed unauthorised. Iran's deputy foreign minister said the US decision to renew its naval blockade of Iranian ports had "dismantled" the Islamabad memorandum. Trump also briefly imposed a 20% toll on ships transiting the strait — a policy his own Secretary of State Marco Rubio had ruled out weeks earlier — before abruptly scrapping it following what the president described as productive conversations with Gulf Arab leaders.

Analysts are divided on what the military campaign can achieve. Some experts note that Iran's capacity to attack vessels in the strait has been measurably degraded, with oil still flowing — the US energy secretary reported 15 million barrels passing through the strait in a single day. Others caution that the physical geography of the strait, where even small numbers of missiles or fast attack craft can threaten large vessels, means Iran retains significant disruptive capability regardless of how many shore-based assets are destroyed. Iran's willingness to act on a threat it held in reserve for decades reflects what analysts describe as a profound shift in its risk calculus: a new leadership that frames every loss as a sacred debt to be repaid, making conventional deterrence harder to apply. The IRGC's decentralised "mosaic defence" strategy also complicates efforts to identify and eliminate command structures.

Trump's threat to strike power plants and bridges would, if carried out, almost certainly violate international humanitarian law, which prohibits attacks on civilian infrastructure. With prospects for renewed negotiations described by experts on both sides as dim, and Iran's new supreme leader having explicitly committed to using the strait as leverage, the conflict risks becoming a prolonged war of attrition — with severe consequences for global energy markets and regional stability.