In 1939, United States President Franklin D. Roosevelt instructed members of the United States Antarctic Service Expedition to take steps to claim some of Antarctica as United States territory. Although this appears to have been done by members of this and subsequent expeditions, these do not appear to have been formalized prior to 1959, when the Antarctic Treaty System was set up. Some publications in the United States have shown this as a United States territory in the intervening period, and the United States Defense Department has stated that United States has a solid basis for a claim in Antarctica resulting from its activities prior to 1959.[2] The portion west of 150°W is part of Ross Dependency claimed by New Zealand.