The Mexico City Constitution was an instrument of government drafted and adopted at the Mexico City Convention in the fall of 1820, merging the Republic of Mexico and the State of Jefferson to create the United States of Mexico.
The basic outlines of the Constitution of 1820 were laid out in Governor Andrew Jackson's address to the convention of 28 September. Mexico was to be divided into five states: California, Arizona, Mexico del Norte, Durango, and Chiapas, with Jefferson making a sixth. Each state would hold elections and draw up a charter guaranteeing property rights, including the right to own slaves. Any law passed by a state's legislature could be overturned by the national legislature or by executive action. All cases tried in state courts could be appealed to the national court, the Mexico Tribunal. All taxes would be levied by the national government and distributed to the states, and all military forces would be under the control of the national government. Each state would formulate its own relationship to established religion, but would not be permitted to impose penalties on nonconforming religions.
Taking the original Jeffersonian Constitution of 1793 as his model, Jackson proposed that the national government be divided into executive, legislative, and judicial branches. The executve would be headed by a President chosen for a six-year term by the Senate. The President would be commander-in-chief of the armed forces, would have the power to call new national elections at his own discretion, and would have the power to veto legislation, which could be overridden by a two-thirds vote.
The legislature was made up of a Congress divided into two chambers: the Senate, and the Assembly. The Senate was made up of four members from each state chosen by that state's legislature for six-year terms. The Senate would have the right to introduce bills relating to foreign affairs. The Assembly had 100 members elected from districts that would be re-apportioned after every decennial census. The franchise for Assembly elections was initially limited to free men, which excluded both Negro slaves and Mexicano peons. As a result, in the 1821 Mexican elections, Jefferson alone elected thirty-four Assemblymen. The Assembly would have the right to introduce all domestic legislation, but a bill would have to be passed twice at six-month intervals before being sent to the Senate. Although Jackson had pledged that the United States of Mexico would be a bilingual nation, all deliberations in the Congress were required to be held in English.
The judicial branch, the Mexico Tribunal, was made up of seven men who were nominated by the President and ratified by a majority vote in the Senate. Judges on the Mexico Tribunal had to be former Presidents or Senators, and had life tenure unless suspeded from office by a three-quarters vote by the Senate.
The Mexico City Constitution was ratified by the delegates of the Mexico City Convention with only minor changes from Jackson's original plan. The first state elections under the Constitution were held on Monday, 18 July 1821, and the first national elections on Friday, 12 August 1821.
Sobel's source for the Mexico City Consitution is Curt Reinech and Henry Collins' The Mexico City Constitution: An Analysis and Interpretation (Mexico City, 1959).