The head of government () wields executive power in Mexico City. The head of government serves a six-year term, running concurrently with that of the president of the Republic. Mexico City, or CDMX, is the seat of national government, and is largely contiguous with the core of the sprawling Mexico City conurbation.
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" but in reality the position does not correspond to the mayor of a municipality. Even though the position is called head of government, it has the rank of governor of a state and has a seat on the National Governors Conference.
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 6 July 1997, with a 47.7% share of the vote in an eight-candidate 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, who was also the son of well renowned former Mexican President Lázaro Cárdenas, would then become the first ever elected head of government for Mexico City after being sworn into office on December 5, 1997. However, his time as head of government would also be marred by numerous administrative failures. Cárdenas later resigned to compete in the 2000 presidential campaign and left in his place Rosario Robles, who served out the remainder of his term.
The head of government elected for the 2000âÂÂ2006 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 7 April 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 Andrés Manuel López Obrador.
All the heads of the Federal District Department since the enactment of the 1917 Constitution were members of the Institutional Revolutionary Party (PRI) or its predecessor parties, and all the popularly elected heads of government since 1997 have been from center-left parties or party coalitions.