In the twentieth century humanity experienced horrific episodes, such as the Armenian genocide, the Holocaust, the genocide from Rwanda, the communist mass terror or the massacres perpetrated in former Yugoslavia. Particular groups, identified as the enemy, the threat or simply the dangerous "other", have been subject to policies of discrimination, exclusion and in the end to policies of extreme mass violence. The most natural questions are Why? and How?. This book focuses on the link between ethnic nationalism and genocide by analyzing the cases of Serbia and Romania. The ideology that guided Romanian and Serbian elite towards genocide was based on national arguments- protecting and preserving the national identity, the uniqueness of the nation (supposedly based on religion, ethnicity), the alleged interests and values of the nation taking priority over all other interests and values. The two cases can help us understand the significance of nationalism in the radicalization of a conflict. Contrary to what some scholars believe, nationalism did not loose its power and can still play a decisive role in unstable regimes with a clear differentiation between ethnic and religious groups