[6] The campaign and the elections took place during a tense period: the government's conflict with the private sector, the mounting economic issues (which would lead to a devaluation of the peso a month after the election), the leftist guerrilla uprisings in some parts of the country and the Dirty War the government took against them were some of the issues that outgoing President Luis Echeverría faced and which jeopardised the power of the ruling PRI.

2,730 people were asked to choose which contender, in their opinion, better fit the following criteria: Muñoz Ledo would later recall that during this period, he received a visit from President Echeverría.

Muñoz Ledo understood the phrase as meaning that he would be the chosen one to succeed him as President, interpreting Echeverría's comment as referring to the PRI delegations that would visit his house to congratulate him on his nomination, and so he decided to buy the land that was behind the garden so as to enlarge it.

[10] In June 1975, Echeverría privately told López Portillo that he would be his successor,[11] and on 5 October he was officially nominated by the PRI as its presidential candidate for the 1976 elections.

[14] Echeverría would later state that he chose López Portillo to succeed him because, as president, "I was aware that the country's main problem was the financial one", which should be faced by his Secretary of Finance, "who had shared with me the attacks of a reactionary and obtuse private sector, which did not hesitate to place its funds abroad in their eagerness to break me down".

[18][19] In his campaign, López Portillo defended the infamous acarreo ("hauling", the practice of trucking people to rallies to cheer its candidates in exchange for gifts of some kind),[20] saying that the attendees "are not ‘hauled’, they are ‘transported’ by the Party's own men and forces", adding that "All organized truck drivers in Mexico are part of the PRI and it is a tradition for them to take their vehicles to transport people to public events".

[21] He further justified in his autobiography that there was "no reason not to facilitate, for example, to our peasants, transportation to public meetings, who concur, after all, to communicate with a System that governs them, through understandable acts in which they participate, see, hear, learn, express themselves and even, are distracted with trips and companies.

There were many rumours that outgoing president Luis Echeverría was planning to carry out a coup d'état against his own candidate, López Portillo, to perpetuate himself in power.