World War I, World War II and the Cold War were fundamentally different conflicts. There were many issues in WWI that were present in WW11 but eventually the two war were different. A lot say that the WWI shaped WWII yet a lot of things in 1920s such as the great depression made this impossible. Furthermore, the alliances in WWI were not fluid as those in WW11.  Until Germany was invaded, the Soviet Union was the closest friend. Notably, the US stayed in isolation and never supported anyone until Pearl Harbor. Japan, on the other hand, did not communicate with anyone until WWII, and the Italians and Germany read the news regarding the Pearl Harbor on the newspaper. As such, it is conclusive that the allies that were experienced in the WW11 were mostly as a result of retaliation and nothing had been organized (Betts, 2015).

Looking at Germany, when it was busy trying to topple Stalin, Japan did not take part in this neither was it hostile while the programs of Hitler focused on it. It became more ironical when you realize that when Japan was attacking China, Hitler offered the support, as such, it is conclusive that the two countries fought different wars (Iriye,2014).

The history of the 20th century was dominated with greedy for supremacy; every state wanted to show the other that they were superior both economically and politically. The warfare also explains how unity among states can be achieved only during the war period as some states took sides just to support other in the war.

Since 1989, a lot of changes have occurred, for instance, the emergence of technology that was off limit to the public such as an internet. Modernism and the notion of absolute ideology and progress has replaced the idea of postmodernism  

References

Betts, R. K. (Ed.). (2015). Conflict after the Cold War: arguments on causes of war and peace. 

Routledge

Iriye, A. (2014). The origins of the Second World War in Asia and the Pacific. Routledge.