Final answer:
Franz Joseph's attempts to reform Austria-Hungary failed due to nationalist tensions, military intervention, and conservative opposition.
Step-by-step explanation:
Franz Joseph's attempts to reform Austria-Hungary failed due to a combination of factors. The Austrian Empire was a diverse collection of ethnic groups with different nationalist aspirations. The revolutions of 1848, which swept through Europe, resulted in demands for independence and constitutional reforms in various regions of the empire.
The Austrian government, with the assistance of Russian military intervention, quashed these uprisings and restored control, effectively ending the chances of successful reforms. Additionally, the conservative forces within Austria and Prussia sought to maintain their power and influence, opposing the revolutionary movements and rolling back any reforms that were proposed.
In summary, Franz Joseph's reform attempts were undermined by the diversity and nationalist tensions within the empire, the military intervention by Russia, and the conservative backlash against the revolutionary movements of 1848.