In the wake of Napoleon’s 1808 invasion of Iberia, Spaniards fought for independence at home while struggling to hold the empire together. That complex and conflictive process led to the 1812 Cádiz Constitution, a document offering citizenship and electoral participations to Hispanic and indigenous peoples, while limiting the rights of men of African origins as slavery expanded in Cuba. That charter shaped political visions and debates in the Iberian world—Spain, Portugal, and their Americas—into the nineteenth century even as military men took the lead in founding and ruling national states. Ironically, a charter designed to hold an empire together in trying times proved most influential, shaping politics in nations that broke away.