Spanish attempts to reconquer Mexico
Mexican independence was officially achieved on September 27, 1821, under the Treaty of Córdoba. Spain did not recognize the treaties, arguing that the viceroy Juan O'Donojú had no authority to recognize the independence of any overseas province. This situation was dangerous to the newly acquired independent status of the nation, which had not yet been recognized by any of the European powers that could support it, and the threat of Spanish reconquest was a constant worry to the leaders of the nascent regime. On May 13, 1822 decrees were issued by the government to imprison anyone who conspired against Mexico's independence.
List of constitutions of Mexico
Since declaring independence in 1821, Mexico has adopted a number of constitutions or other documents of basic law with constitutional effects. Not all these can be considered constitutions, and not all of them enjoyed universal application. Those enacted in 1824, 1857, and 1917 are generally considered full-fledged, operational constitutions. The Constitution of 1824 established the framework of a federated republic, following the short-lived monarchy of Agustín de Iturbide (in 1821–22). The Constitution of 1857 was the framework set by Mexican liberals that incorporated particular laws into the constitution. The Constitution of 1917 was drafted by the faction that won the Mexican Revolution, known as the Constitutionalists for their adherence to the Constitution of 1857. It strengthened the anticlerical framework of the 1857 constitution, empowered the state to expropriate private property, and set protections for organized labor. The 1917 Constitution was significantly revised in 1992 under Carlos Salinas de Gortari, eliminating anticlerical restrictions and strengthening private property rights against the State.