The crisis in the Strait of Hormuz has exposed a structural vulnerability that Western policymakers have spent three decades ignoring. The problem is not Iran. The problem is that the global economy built its energy architecture on the assumption that a 21-mile-wide waterway between two hostile shores would remain permanently open.

That assumption was always precarious. It survived the Tanker War of the 1980s, the post-9/11 tensions, and repeated Iranian threats to close the Strait during the nuclear negotiations of the 2010s. Each time, the waterway remained open, and each time, policymakers concluded that the risk was manageable. They were not wrong about those specific episodes. They were wrong to extrapolate from them a general rule.

The current closure — partial, contested, and ambiguous as it is — has demonstrated what disruption actually looks like. Oil above $100. Japanese strategic reserves depleting at an unprecedented rate. European gas prices spiking on LNG diversion fears. Insurance premiums for Gulf-bound tankers at levels not seen since the Second World War. And this is the mild version. A full, sustained closure would be catastrophic.

The lesson is not that the West needs better military options in the Gulf, though it does. The lesson is that energy security cannot depend on a single chokepoint controlled by no one and threatened by everyone. The transition to renewable energy, often discussed in terms of climate policy, is at its core a strategic imperative. Every megawatt of solar or wind capacity installed in Europe or Japan is a marginal reduction in dependence on a waterway that has now proven it can be shut.

None of this will happen quickly. The infrastructure of energy dependence was built over generations and will take at least one more to dismantle. But the Hormuz crisis should end the debate about whether diversification is necessary. The only remaining question is how fast it can be achieved.