durée de vie des États-nations

The "durée de vie des États-nations" refers to the lifespan or stability period of nation-states—countries with defined borders, government, and identity. Historically, some nations have existed for centuries, while others evolve, merge, or dissolve due to political, economic, or social changes. Factors influencing their longevity include leadership stability, economic prosperity, internal cohesion, external relations, and global geopolitical shifts. Understanding this concept helps us see how nations develop, adapt, or sometimes decline over time, highlighting the dynamic nature of geopolitical identities and borders.