Las Siete Leyes (, or Seven Laws was a constitution that fundamentally altered the organizational structure of Mexico, away from the federal structure established by the Constitution of 1824, thus ending the First Mexican Republic and creating a unitary republic, the Centralist Republic of Mexico. Formalized under President Antonio López de Santa Anna on 15 December 1835, they were enacted in 1836. They were intended to centralize and strengthen the national government. The aim of the previous constitution was to create a political system that would emulate the success of the United States, but after a decade of political turmoil, economic stagnation, and threats and actual foreign invasion, conservatives concluded that a better path for Mexico was centralized power. Las Siete Leyes were replaced in 1843 by the Bases Orgánicas.