Events in Spain directly weakened Spanish control, spread new political ideas, and triggered key turning points that both started and ended the Mexican fight for independence.

Background: Spain in Crisis

  • In the early 1800s, Spain was rocked by the Napoleonic Wars, foreign invasion, and internal political struggles between liberals and absolutists.
  • This turmoil undermined royal authority across the empire, including New Spain (Mexico), making colonial control weaker and more uncertain.

How Spain’s Problems Sparked Rebellion

  • The crisis in Spain convinced many in New Spain that Spain could no longer guarantee stable or fair government, encouraging local elites and common people to consider independence.
  • As Spanish power faltered, Mexican leaders like Miguel Hidalgo and José María Morelos used the moment to launch uprisings in 1810, arguing that local people should rule themselves.

Enlightenment and Liberal Ideas from Spain

  • Spanish liberal politicians and the Cortes of Cádiz promoted ideas like constitutional government, popular sovereignty, and limited monarchy, especially in the 1812 Cádiz Constitution.
  • These ideas spread to Mexico, inspiring revolutionaries to demand not only separation from Spain but also new forms of government and rights within Mexico.

Local Power Vacuums and Juntas

  • As the Spanish monarchy struggled and communication broke down, local governing councils (juntas) formed in parts of the empire to fill the power vacuum.
  • In Mexico, this encouraged Creole elites to take more control locally, further weakening loyalty to the distant Spanish crown.

Spain’s 1820 Liberal Revolution and Independence

  • In 1820, a liberal revolution in Spain forced King Ferdinand VII to restore the constitution, alarming conservative elites in New Spain who feared losing their privileges.
  • Ironically, this liberal victory in Spain pushed Mexican conservatives and rebels to unite behind Agustín de Iturbide’s army, which quickly brought down Spanish rule and led to independence in 1821.

Cause-and-Effect Summary

  • Spain’s wars and political chaos weakened its grip on Mexico and opened space for revolt.
  • Spanish liberal experiments and constitutionalism spread new political ideas that Mexican leaders adapted to their own independence project.
  • The final liberal revolution in Spain (1820) frightened Mexican conservatives, causing them to join the independence cause and helping bring the long war to an end.

TL;DR: Events in Spain—Napoleonic invasion, civil conflict, and liberal revolutions—first weakened royal control, then spread reformist ideas, and finally pushed Mexican elites to choose independence as the safest way to protect their interests and create a new national government.

Information gathered from public forums or data available on the internet and portrayed here.