According to Article 122 of the Constitution+, "the Head of Government of the Federal District shall be responsible for executive power and public administration in the district and shall be represented by a single individual, elected by universal, free, direct, and secret suffrage."
The title is commonly rendered in English as "Mayor of Mexico City" or (less frequently) as "Governor of the Federal District" (as the position was known in the early post-Revolution+ years), but in reality the position does not correspond exactly to either the mayor of a municipality ''(presidente municipal+)'' or the governor of a state+ ''(gobernador+)'' as they are understood in Mexican law.
For the greater part of the 20th century, the D.F. was administered directly by the President of the Republic+, who delegated his authority to an appointed Head of the Federal District Department, known more commonly (and tersely) as the ''Regente'' ("Regent" in English). This non-democratic imposition was a source of constant and often bitter resentment among the inhabitants of Mexico City. Under the reforms of the state introduced by presidents Carlos Salinas+ and Ernesto Zedillo+, the Regent was replaced by the first directly elected Head of Government in 1997.
On July 6, 1997, with a 47.7% share of the vote in an eight-horse race, Cuauhtémoc Cárdenas+ won the first direct Head of Government election (this first term was to last only three years, to bring the office into line with the presidential succession). Cárdenas, a former presidential candidate who was, according to many, cheated out of victory in the closely fought 1988 presidential election, later resigned to compete in the 2000 presidential campaign+ and left in his place Rosario Robles+, who served out the remainder of his term as the first woman to govern Mexico City.
The Head of Government elected for the 2000–2006 term was Andrés Manuel López Obrador+, elected with 39% of the popular vote in the same election that saw Vicente Fox+ of the PAN+ win the presidency. López Obrador was temporarily removed from office by the federal Congress+ on April 7, 2005 and was replaced, on an interim basis for a period of slightly over two weeks, by his secretary of government, Alejandro Encinas+. See desafuero of AMLO+.
* Gen. Cesar Lopez de Lara+: August 3, 1915 (By the decrees of 3/12/1914 based on the Plan of Guadalupe+, federal capital city of Veracruz and January 5, 1917 decree establishing the capital in the city of Querétaro. The changes of residence were never ratified by Congress)