Comparison between Realism and Liberalism

Liberals believe in inter-dependency, all they want is peace by cooperation, while realist think there is no any other way to solve an issue than go to war, realist tend to be skeptical, the world is dangerous and cruel and human naturally is mean, ambitious and evil, you’ll never know today’s friend can be tomorrow’s enemy if you cooperate one to another, who is now an alliance or probably right now is planning to stab you from the back, that you will always need power in order to prevent this to happen even though you can never have enough power, while liberals believe human nature is kind-hearted. Realism is pessimistic seeing that human is kind otherwise the liberals being optimistic.

The Differences 

Realism	Liberalism
Human being is cruel.	Human being is kind.
There is no room for negotiation, cooperation, organisations.	There are organisations and cooperations
State is the only actor	State and non state actors
Struggle of power and security	Focuses on economy and political aspects
State is selfish and always seek power	State is being rational
Being pessimistic and see the world as it is	Being optimistic and see the world as it should be

The Similarity

Realism	Liberalism
State is the main actor
Both care about self interest and national interest
Anarchy
Focus on international system