 The U.S.-led campaign against the Houthi rebels, overshadowed by the Israel-Hamas war in Gaza, has turned into the most intense running sea battle the Navy has faced since World War II, say our Navy's leaders. The combat pits the Navy's mission to keep international waterways open against a group whose former arsenal of assault rifles and pickup trucks has grown into a seemingly inexhaustible supply of drones, missiles, and other weaponry.