How does this quote by aristotle relate to wwii and the cold war? did we follow his advice after world war one? did we follow it after world war two?

After World War I: No--The peace agreement following World War I was punishing and focused on revenge and pay back instead of creating a lasting peace. 

Britain and France believed they were creating peace for themselves, but created hostility with Germany. 

After World II: yes and no--Peace was achieved in that a full scale world war has not occurred again and a working peace organization has been established withe the UN. However, the Cold War was an expensive and scary time of tension with no relationship between the two world powers. 

World War II created a more balanced peace allowing countries freedom from colonization and reduction of world threats. The advancement of technology to include nuclear weapons kept the world at relative peace through fear and deterrence. The check of two major opposing super powers kept the world mostly peaceful. 

Wait u answered your own question