The idea of basing the Superfortresses in China first surfaced at the Casablanca Conference in January 1943. While planners assessed this option, the Anglo-American Combined Chiefs of Staff, meeting in Quebec in August, authorized a central Pacific drive that included the seizure of the Mariana Islands. Not only were the Marianas closer to Tokyo, but once in Allied hands they could be supplied and defended more easily than other sites. In September, Combined Chiefs of Staff planners concluded that B-29s in China, isolated from resupply except by inclusion in the Hump airlift, would be plagued by logistical problems. However, President Franklin D. Roosevelt decided in favor of the China bases because he was impatient to bomb Japan and wished to bolster the Chinese war effort. At the Sextant Conference in Cairo at the end of the year, he promised Chiang Kai-shek that the very heavy bombers would be coming to his country. General Henry H. Arnold supported that decision as a temporary expedient, but still preferred strategic missions against Japan from the Marianas, once bases there were available. The operation was originally called "Drake", with the use of long-range B-24s as well as B-29s.