In the United States, military and foreign policies are most obviously shaped by the president. Presidential personality clearly influences the sort of decision-making process each incumbent feels comfortable with: whether he prefers oral or written interactions, has an appetite for detail, or can tolerate conflict among and with subordinates. A review of the personal styles of five American presidents reveals three broad approaches that can be categorised as 'formalistic', 'competitive' and 'collegial'. The first approach, often associated with President Dwight D. Eisenhower, emphasises order and hierarchy. The second, epitomised by Franklin Delano Roosevelt, seeks wisdom through the clash of ideas among competing subordinates. The third, identified with George H.W. Bush, encourages greater cooperation among these advisers. As these examples suggest, all three models can yield excellent results. They can also produce quite unsatisfactory outcomes.