A military conflict between Iran and Israel, which now also involves the United States, could disrupt oil and natural gas shipments through a critical waterway. That slender route alongside Iran, named the Strait of Hormuz, links the Persian Gulf and Gulf of Oman. A significant share of oil and gas exports pass through that only lane from regional ports to the Arabian Sea.

It's in the news after America on June 22 joined Israel's bombing campaign against Iran by dropping powerful munitions on three nuclear weapons program sites. After 12 days of missile exchanges by the two Mideast enemies, President Trump said he acted to neutralize a threat "posed by the world's number one state sponsor of terror." Because Iran controls the northern side of the strait, a "chokepoint" just 21 miles wide at its narrowest, it can slow or block shipping by deploying explosive naval mines via submarines. It also can threaten ships with fast-attack boats, drones or missiles. (Oman and the United Arab Emirates control the passage's southern side.)

Reduced traffic through the strait could drive up oil and gas prices by cutting supplies from Saudi Arabia and other ports, which would hurt energy exporters – including Iran itself - and shake economies worldwide. China, India and Japan are among the top importers of crude oil passing through the strait, pronounced HOAR-mooz. Before missile volleys paused last week, Israel and Iran damaged each other's energy assets. Targets have included an Iranian natural gas field, its main gas depot in the capital (Tehran) and Israel's largest oil refinery. "You're going to see the stock markets reacting very nervously to what's happening," says Bader Al-Saif, an assistant professor at Kuwait University who specializes in politics of the Arabian Peninsula. In Washington, economist Clayton Seigle at the Center for Strategic and International Studies says: "The world can't do without that energy supply. A cutoff would be an unprecedented, severe blow to the global economy."

That possibility is on hold, at least for now, because a fragile truce between Israel and Iran has been in place since last Tuesday. If war flares again, blocking commercial shipping is a way Iran can punish and pressure Israel and America. "If the cease-fire collapses and war resumes, Iran may choose to . . . close the Strait of Hormuz," international affairs professor Vali Nasr of Johns Hopkins University wrote last week in The New York Times. Amid the uncertainty, maritime insurers have raised rates on U.S. and Israeli vessels using the strait. U.S. involvement presents one of the biggest challenges to Iran since the Islamic Republic's founding in 1979. The future of its nuclear program and the tenuous cease-fire depend on Ayatollah Ali Khamenei, who has maintained his nation’s hostility to the West during 36 years in power. As he sees it, sees it, Iran is in a struggle for survival with America and its allies, including Israel.

U.S. official says: Blocking the strait "would be a suicidal move on Iran's part because, I think, the world would come against them." – Marco Rubio, secretary of state

Expert says: "Iran has the capacity to disrupt shipping in the Strait of Hormuz. But in the face of a determined U.S. response, Iran is not capable of completely closing the strait." -- Daniel E. Mouton, who was on the National Security Council from 2021-23

Volume of fuel transports: A daily average of 20.3 million barrels of petroleum products, mostly from Saudi Arabia, went through the strait in 2024. So did 290 million cubic meters of liquid natural gas, mainly from Qatar.