What is the difference between liberalism and realism in international relations?

Realism and

idealism are two dominant models in global politics. They have

contrasting ideas when it comes to explaining how states relate to

each other in the absence of a world government. The realist

ideology want to emphasis the preservation of the state through

sovereign dominance as necessary condition for its survival whereas

the idealist believe in state cooperation and common interests so

that a greater good can be achieved acting collectively than by

states acting purely out of national interests.