The ceasefire in Iran represents a victory of sorts for Tehran, which has gained a powerful insight into the potency of its energy weapon.

Oil prices plummeted below $100 per barrel after US President Donald Trump agreed to a two-week truce and Iran’s foreign ministry said in a statement that during that time, “safe passage through the Strait of Hormuz will be possible via coordination with Iran’s Armed Forces and with due consideration of technical limitations.” As has been the case throughout the last five-plus weeks of war, the rapid change in oil price reflects traders’ gut feelings more than a tangible change in physical flows; although some already-full tankers that have been idling outside the strait could quickly move to market, it will take weeks or even months for onshore production facilities to ramp up and for empty tankers around the world to actually reach ports in the Gulf — and that’s assuming the ceasefire holds, which already appears dubious.

In the meantime, Tehran appears to be in a stronger position vis-a-vis the strait than it was before the war. In addition to roughly doubling its income from oil sales over the past few weeks, “the war is pausing with the Iranians effectively in control of the strait,” Gregory Brew, senior oil analyst at Eurasia Group, told me. No oil or gas tankers passed through on Wednesday, and Tehran has indicated it will charge tolls (in cryptocurrency or yuan) for passage, which historically had been barred under international law. “Let’s be clear: the Strait of Hormuz is not open,” Sultan al-Jaber, CEO of ADNOC, wrote in a post on Thursday. “That is not freedom of navigation. That is coercion.” And if Washington allows that level of control to persist, “then this will clearly indicate that the war has ended in something of an Iranian victory,” Brew said.

While the conflict ostensibly started over Iran’s drive for nuclear weapons, among other things, a key lesson so far is that it may not even need them. Rather than a decades-long, expensive, and risky campaign to build a nuke — a weapon that, if ever used, would guarantee Iran’s own annihilation — Tehran has learned that by closing the strait, it can fairly easily exact massive pain on the US and the global economy in a way that actually benefits its own coffers.

According to reporting this week in The New York Times, Trump and his aides greatly underestimated the risk to oil markets stemming from the war, believed the war would be over before Iran had a chance to close the strait, and didn’t include top energy officials in critical decision-making. Those are mistakes the US can’t afford to make again.

A more sustainable victory for the US will require much more than propping up a more favorable regime. Instead, as Biden administration energy official Amos Hochstein argued in The Atlantic this week, the most important security measure moving forward will be to eliminate the strait as the energy bottleneck it has plainly been for decades, by working with allies across the region and globe to build new pipelines, ports, nonfossil energy sources, and other work-arounds.