Why was the idea of self-determination affected by the peace treaties?

The idea of self-determination was affected by the peace treaties because the treaties imposed new boundaries and created new nations without always considering the desires and rights of the populations affected. This led to the dissatisfaction of various ethnic groups who felt their right to determine their own political status was disregarded. The treaties also resulted in the establishment of nation-states that did not always align with the self-determination aspirations of minority groups within their borders.