An early obstacle was a desire by both the army and Roosevelt to initiate action in Europe. In addition, it was unclear who would command the campaign: Tulagi lay in the area under the command of General Douglas MacArthur, whereas the Santa Cruz Islands lay in Admiral Chester W. Nimitz's Pacific Ocean Area, which would also supply almost all offensive forces that would prepare and be supplied and covered from that area. Both problems were overcome, and the Chief of Staff of the U.S. Army, General George C. Marshall, gave the operation his full support, even if MacArthur's command could not lend support and the navy had to take full responsibility. As a result, and in order to preserve the unity of command, the boundary between MacArthur's Southwest Pacific area and Nimitz's Pacific Ocean area was shifted to to the west effective 1 August 1942.