Final answer:
The EU faces long-term challenges such as maintaining unity among diverse members, managing demographic shifts and the related economic sustainability concerns, aligning national and EU-wide interests, and navigating international relations amidst global competition.
Step-by-step explanation:
One of the long-term challenges facing the European Union (EU) over the next fifty years is maintaining unity among its member states while addressing diverse economic, political, and social issues. The EU's mission to ensure peace and prosperity involves navigating international relations and responding to global competitive pressures, demographic shifts, and technological changes. Challenges such as the decline in family size leading to an aging workforce, pension sustainability, and the integration of immigrants must be addressed to maintain social cohesion and economic stability. Moreover, the EU must balance its internal aspirations with external pressures such as the geopolitical ambitions of Russia and China.
EU member states must also deal with the need to create a shared 'European identity' despite cultural, political, and economic diversity. Environmental challenges and the emergence of the digital economy are transforming the world and require a well-coordinated response from the EU to ensure long-term viability. Together, these issues represent a complex array of challenges that require concerted efforts at both national and EU levels to manage effectively.