Article 32 Political Constitution of the United Mexican States

The law shall regulate the exercise of the rights that Mexican legislation grants to Mexicans who possess another nationality and shall establish rules to avoid conflicts due to dual nationality.

The exercise of the positions and functions for which, by provision of this Constitution, it is required to be a Mexican by birth, is reserved to those who have that status and do not acquire another nationality. This reservation shall also be applicable to the cases that other laws of the Congress of the Union so indicate.

In time of peace, no foreigner may serve in the permanent Armed Forces, nor in the police or public security forces. To belong to the active service of the Army in time of peace and to that of the Navy or to that of the Air Force or to that of the National Guard at all times, or to hold any position or commission in them, it is required to be a Mexican by birth.

This same status shall be indispensable in captains, pilots, masters, machinists, mechanics and, in a general manner, for all personnel who crew any vessel or aircraft that is protected by the Mexican merchant flag or insignia. It shall also be necessary to hold the positions of port captain and all pilotage services and airfield commander.

Mexicans shall be preferred to foreigners, under equal circumstances, for all kinds of concessions and for all employments, positions or commissions of government in which the status of citizen is not indispensable.