The Houthis, militants in Yemen backed by Iran, have fired over 100 drones and missiles at ships linked to more than 35 countries, ostensibly in support of the Palestinians. Their campaign is an affront to the principle of freedom of navigation, which is already at risk from the Black Sea to the South China Sea. America and its allies must deal firmly with it—without escalating the conflict in the Middle East. For the world to prosper, ships must reach their ports. They are most vulnerable when passing through narrow passages, such as the Strait of Malacca or the Panama Canal. Will America handle all these crisis it is causing ?