Yemen’s Iran-backed Houthi rebels are launching attacks despite a month of U.S.-led airstrikes. This week they seriously damaged a ship in a strategically important strait and apparently downed an American drone worth tens of millions of dollars. Their assaults on shipping through the crucial Red Sea corridor amid Israel’s war on Hamas in Gaza underscore the challenges in trying to stop their guerrilla-style attacks. Analysts warn that the longer their attacks go on, the greater the risk to the global economy. Meanwhile, the U.S.-led campaign has boosted the rebels’ standing in the Arab world, despite their human rights abuses in a longer, stalemated conflict with U.S. allies.