The Houthis, an Iranian-backed militia in Yemen, have learned to fight on their own and now control the Bab al-Mandab, a strait connecting the Red Sea and the Gulf of Aden. This waterway has become critical for Saudi Arabia's oil exports since Iran closed the Strait of Hormuz.

Vivian Nereim, lead reporter in the Gulf states, noted that "geography can be power, even for the most seemingly unlikely group." Just as Iran's proximity to the Strait of Hormuz allowed its forces to disrupt traffic, the Houthis' strikes along the Red Sea coast have given them command of a waterway that may play an even bigger role in global shipping.

The Houthis started in the 1990s as a religious movement in northern Yemen, later becoming Islamist fighters waging civil war. Supplied by Iran, they battled a Saudi-led coalition until the UN brokered a fragile peace in 2022. They have since grown more sophisticated. A report from Anthropic suggested people in northern Yemen used the company's A.I. assistant to develop guided weapons, including a ballistic missile with a range of 1,200 miles.

The Houthis describe themselves as the liberators and legitimate leaders of Yemen, pitting them against Yemen's Saudi-backed government. They also want access to Yemeni oil revenue and war reparations from Saudi Arabia.