Admiral Ernest King, the C-in-C of the U.S Navy, was so concerned about losses from "kamikaze" attacks that he and other senior naval officers argued for canceling Operation Downfall, and instead continuing the fire-bombing campaign against Japanese cities and the blockade of food and supplies until the Japanese surrendered. However, General George Marshall argued that forcing surrender this way might take several years, if ever. Accordingly, Marshall and Knox concluded the Americans would have to invade Japan to end the war, regardless of casualties.