One realistic assumption is "Human nature has a dark side." Due to fear, nation states may strike a country before they are striked. Humans want to protect themselves from getting hurt, so to them it is best to hurt a country or person before they have a chance to hurt you. This type of feeling can be caused from mistrust within allies or members of the country. In "Melian Dialogue"the Athenians didn't trust the Melians. They wanted to take control of the Melians before they could potential become enemies. This stems from being power hungry and having mistrust amongst nations. Another realistic assumption is "The international environment inspires fear and mistrust between states, and states therefore see to their own protection." An example
