Over the past month, Iran has made its most intense attacks on shipping in the Strait of Hormuz since the United States and Israel declared war, in February. More than 100 drone and missile launches into the strait have been recorded since the war began; in October alone, a container ship and a bulk vessel sank in the waterway. Meanwhile, in the Red Sea, Yemen’s Iran-backed Houthis have sustained their campaign to throttle seaborne trade as they target Saudi Arabia more directly, seizing new territory along the Bab el Mandeb Strait.

These dual maritime crises form part of the same strategic problem—one that, despite its new intensity, has existed for years. In 2019, Iran attacked shipping across the Gulf in response to the first Trump administration’s maximum-pressure sanctions campaign; in 2023, the Houthis launched assaults in the Red Sea following Hamas’s October 7 massacre in Israel.…