The Strait of Hormuz is reopening, and the oil market has already moved on. Brent settled below $79 a barrel this week, its lowest level since early March and a fourth consecutive session of losses — the longest losing streak of the year. The premium that carried Brent above $114 in March, the fear that priced in a closed chokepoint handling a fifth of the world’s crude, has bled out in the span of a few sessions. The memorandum of understanding signed by Washington and Tehran reopens the waterway without Iranian tolls for at least sixty days and clears Iran to sell oil immediately. Traders are pricing the supply. They are not pricing the wait.

Of all the weapons in Iran’s arsenal for threatening the Strait of Hormuz, the naval mine is the one that demands the most serious attention. It is not the most dramatic option — no missile streaking toward a supertanker makes for better television — but it is the most operationally credible, the hardest to counter, and the one with the longest historical track record of actually disrupting Gulf shipping.

Understanding why requires understanding what mines do that other weapons do not.

Ali Khamenei is in his late eighties. Iranian succession planning is opaque by design but has been visibly active for several years. Whoever follows him inherits a maritime posture built around three decades of Khamenei’s particular preferences: aggressive enough to extract concessions, restrained enough to avoid full war. That equilibrium is personal. It does not survive the man.

The two leading succession scenarios point in different directions. A consolidation candidate from the IRGC orbit, the kind of figure who would emerge if the Guard’s institutional weight wins out, treats the Hormuz card more aggressively. The IRGC Navy’s leadership has spent forty years arguing internally that Iran’s deterrent value is underused. A Supreme Leader drawn from that worldview reduces the threshold for harassment operations and increases the frequency of incidents in the Gulf. Markets price this as a tail risk that gets fatter.

For most of the post-revolution period, Iran’s maritime threat was a Hormuz threat. Its proxies were land-based, oriented against Israel and US forces in Iraq and Syria. Sometime around the middle of the last decade, Iran began transferring serious naval capability to the Houthis in Yemen, and the maritime threat picture extended to Bab el-Mandeb. The campaigns of recent years demonstrated what that capability looks like in practice. The Iranian theory was that a distributed maritime threat across two chokepoints multiplied leverage. The actual result was that Iran lost control of half its maritime card.

Iran has reportedly floated a deal: reopen the Strait of Hormuz in exchange for postponing nuclear talks. The framing is generous to Tehran on its face. It treats two unrelated problems as commensurate, and it trades a closure Iran has no right to impose for a delay on the only question that actually matters. Accepting it would not advance American policy. It would erase it.

Hormuz is a tactical disruption. The strait carries roughly a fifth of global oil shipments and any closure produces a real price spike, but the disruption is also temporary. Tankers reroute. Insurance markets adjust. Naval coalitions form. Every closure threat in the past four decades has ended the same way: the price comes down, the ships move, and Iran absorbs the political cost of having weaponized international waters. UNCLOS does not recognize Iran’s authority to close the strait in the first place. Treating its reopening as a concession is to legitimize a blockade that has no legal foundation.

The threat to close the Strait of Hormuz is the oldest line in Iranian deterrence. It has been recited since the Iran-Iraq War, repackaged after every sanctions tightening, and trotted out reflexively whenever a US carrier strike group enters the Gulf. The line works because the audience accepts the premise: that Iran could close the Strait if it wanted to. The premise is half true. Iran has the capability to disrupt traffic for days, possibly weeks. What it does not have is the capability to survive doing so.

The headline weapons of Iranian maritime strategy are missiles and fast boats. The actual weapon, the one that has done the most damage at the lowest cost across four decades, is the sea mine. Mines are unglamorous, undermarketed, and operationally devastating. Any serious analysis of a Hormuz contingency starts with them.

Iran’s mine inventory is large and varied. Estimates run to several thousand devices, ranging from refurbished Soviet contact mines to indigenous influence mines triggered by acoustic, magnetic, or pressure signatures. Some are tethered. Some are bottom-laid. Some are smart enough to count ship signatures and ignore the first several passes before activating. The technological floor is low. The technological ceiling is high enough to challenge even modern minesweeping.

The Strait of Hormuz is irreplaceable for Iran. It is increasingly optional for everyone else. Two decades of Gulf state infrastructure investment have built a parallel export system that bypasses the corridor entirely, and the trend is accelerating. The strategic implication is that Iran’s chokepoint leverage is depreciating in real time.

Saudi Arabia’s East-West pipeline, the Petroline, runs from Abqaiq to Yanbu on the Red Sea. Capacity has been expanded incrementally and now sits near five million barrels per day. In a Hormuz disruption scenario, the Saudis can route the bulk of their crude to a Red Sea terminal that exits via Bab el-Mandeb, a strait the Houthis can harass but the kingdom can defend more easily than a Gulf corridor ringed by Iranian territory. Yanbu is not a perfect substitute. It is a serviceable one.

The IRGC Navy has spent three decades cultivating a single image: clouds of fast-attack craft swarming across the Gulf, overwhelming American destroyers through sheer numbers. The image has been reinforced by exercise footage, parade reels, and obliging Western analysts who treat the visual as evidence of doctrine. The doctrine is real. The image, in its operational form, is mostly theater.

A swarm requires three things to function: numbers, coordination, and a target that cannot effectively defend itself. The IRGC has the numbers, several hundred small craft of varying capability, from rebadged Bladerunner hulls to indigenous Peykaap classes. Coordination is harder. Iranian command and control over distributed light units in a contested electromagnetic environment is not what the parade footage suggests. Western jamming, GPS denial, and persistent ISR turn a swarm from a coordinated attack into a collection of isolated boats moving at thirty knots toward ships that detected them an hour earlier.

Iran has invested more systematically in anti-ship missile capability than any other aspect of its naval force development over the past three decades. The investment reflects the operational logic of the IRGCN’s Hormuz doctrine: surface ships and tankers transiting the strait in a contested environment must be threatenable from multiple vectors simultaneously, and missiles — launched from shore, from surface vessels, from aircraft, and eventually from submarines — provide the most cost-effective way to achieve that coverage. The resulting arsenal is among the largest and most diverse anti-ship missile inventories of any regional power.