Alastair Francis Buchan, the Montague Burton Professor of International Relations for Oxford University, reflects on the global power of the United States of America in his third Reith lecture. Speaking from his series entitled 'Change without War', he reflects on new international relations. In this lecture entitled 'The Troubled Giant', Professor Alastair Buchan explores why the United States of America is still the largest and strongest world power. He analyses how its decisions continue to affect the climate of world politics more than any other country and asks why this continues to be true. He examines the USA's relationship with the power structures within the Soviet Union and China, as well as looking at the triangular economic relationship between the USA, Europe and Japan.