In 2018, pro-government Yemeni forces advanced towards the port city of Hodeidah, the second most important city controlled by the Houthi rebels after the capital, Sanaa.

Away from Yemen’s mountains, the Houthis were struggling to deal with Saudi-led coalition air strikes on the coastal plain south of Hodeidah and were falling back rapidly towards the city. After four years of war, the government side saw an opportunity to severely weaken the Houthis and possibly knock them out of the war.

But it wasn’t that simple. A battle for Hodeidah would likely lead to deadly urban warfare, and the city’s port is a lifeline for Yemenis with the vast majority of the humanitarian aid and economic goods coming into the country through…