Holt cultivated a close relationship with the United States under President Lyndon B. Johnson. He believed that "without the American shield most of us who live in Asia and the South Pacific would have a continuing sense of insecurity". Cooperation between the two countries extended beyond the Vietnam War. Holt approved the construction of several Earth stations for use by NASA and American intelligence agencies, including Pine Gap, Honeysuckle Creek, and Tidbinbilla. This made Australia "the most substantial centre for American missile and space operations outside the continental United States".