The observer examining the development of self-determination in Eastern Europe between the World Wars would likely conclude that practical concerns made it difficult to implement. This is because Eastern Europe was faced with numerous challenges during this period, including economic instability, political unrest, and territorial disputes. These practical concerns often hindered the full realization of self-determination, as governments and societies struggled to address these pressing issues. While self-determination may have encouraged socialism or promoted national unity to some extent, the overarching conclusion would likely be that practical concerns posed significant obstacles to its implementation. Additionally, it cannot be concluded that self-determination promoted peace between nations, as this period saw the rise of geopolitical tensions and conflicts in Eastern Europe.
