The debate between realists is divided into structural realists and human nature realists. Hans Morgenthau, a human nature realist, believes in the will to power. On the other hand, the speaker identifies as a structural realist, attributing competition and war to the structure of the system rather than individual nature. Within structural realism, there is a distinction between offensive and defensive realists. Defensive realists focus on maintaining power, while offensive realists believe states actively seek opportunities to gain more power.