Shortly after Japanese attack on Pearl Harbor, Churchill and his senior military staff used the Arcadia Conference in Washington to decide the general strategy for the war. The American Army Chief of Staff George Marshall came up with the idea of a Combined Chiefs of Staff that would make final military decisions (subject to approval by Roosevelt and Churchill). Marshall sold it to Roosevelt and together the two sold the idea to Churchill. Churchill's military aides were much less favorable, and Brooke was strongly opposed. However, Brooke was left behind in London to handle the daily details of running the British war effort, and was not consulted. The combined board was permanently stationed in Washington, where Field Marshall John Dill represented the British half. The Combined Board did have thirteen in-person full meetings, which Brooke attended.