How did fascism and Nazism ideologically justify expansion?

Fascism and Nazism justified expansion through the ideologies of racial superiority, national rebirth, and the need for living space.

Fascism and Nazism, as political ideologies, were rooted in the belief of racial and national superiority. The Nazis, led by Adolf Hitler, propagated the idea of 'Aryan' supremacy, asserting that the Germanic peoples were the 'master race'. This racial hierarchy was used to justify the expansion of German territories, as they believed it was their right and duty to rule over 'inferior' races. Similarly, Italian Fascism under Benito Mussolini promoted the concept of a 'New Roman Empire', using historical and cultural narratives to legitimise territorial expansion.

Another key aspect of these ideologies was the idea of national rebirth or regeneration. Both Hitler and Mussolini came to power in nations suffering from economic instability and perceived national humiliation following World War I. They promised to restore their nations to their former glory, which involved not only internal restructuring but also external expansion. This was seen as a necessary step to regain lost territories, rectify perceived injustices from past treaties, and reassert their nations' power on the global stage.

The concept of 'Lebensraum', or living space, was a significant part of Nazi ideology. Hitler argued in his book 'Mein Kampf' that the German people needed more space to ensure their survival and prosperity. This was used to justify the annexation of territories, particularly in Eastern Europe, under the pretext of providing space for the growing 'Aryan' population. The idea of 'Lebensraum' also tied into the racial superiority narrative, as it was believed that the 'master race' had the right to displace 'inferior' peoples to secure this living space.

In essence, Fascism and Nazism justified expansion by intertwining ideologies of racial superiority, national rebirth, and the need for living space. These ideologies were used to legitimise aggressive foreign policies and territorial acquisitions, painting them as necessary for the survival and prosperity of their respective nations.