Levy and Székely 1987: "Once the revolutionary warfare was over, a comprehensive federal electoral law was passed by the new Congress in 1918. Voting rights were restricted to literate, married males at least eighteen years old and to literate, unmarried males at least twenty-one years old" (page 65).
Meyer 1985: On July 2, 1918 a new electoral law is published (page 78).
Aguilar Camín 1993: Emiliano Zapata is assassinated on April 10, 1919 (page 65).
Aguilar Camín 1993: Carranza "accused Obregón of conspiring with the rebels and subjected him to a lawsuit for sedition in Mexico City. Obregón escaped...and the Sonorense government and military officers announced in April 1920 the Plan de Agua Prieta, which disavowed the Carrancista government...Carranza, surprised by the turn of events...decided to retreat to Veracruz, recondition his forces, and return victorious to retake the rest of the country...On the night of May 21, 1920, he was assassinated in Tlaxcalantongo...He was buried four days later in Mexico City...on the morning of the day on which Congress would elect Adolfo de la Huerta as substitute president, the civilian head of the Agua Prieta rebellion, and the first in a series of four Sonorense presidents that postrevolutionary Mexico would have in the following fourteen years" (pages 69-70).
Brandenburg 1955: Carranza selects "the conservative and unpopular Ignacio Bonillas" (page 29) to succeed him as president. Obregón and Calles resign their cabinet posts and join Adolfo de la Huerta, governor of Sonora, in issuing the "Plan of Agua Prieta" on April 23, 1920. "On May 24, 1920, the Congress selected Adolfo de la Huerta as Provisional President, effective June 1, and set September 5 as election day for a new constitutional President" (page 30).
Meyer 1985: Congress votes for interim president and Adolfo de la Huerta, governor of Sonora, wins 224 (87%) of the votes (page 80).
Molinar Horcasitas 1991: "La oposición real a Carranza se iba a dar a la hora de su sucesión, pues el viejo revolucionario intentó imponer la candidatura de un civil y solamente logró que su sucesión terminara con su propia muerte en Tlaxcalantongo...(L)a rebelión de Agua Prieta, que culminó con el asesinato del Presidente Carranza, sirvió para establecer con claridad el abrumador dominio político y militar de los revolucionarios sonorenses, sólidamente acaudillados por el invicto revolucionario Alvaro Obregón" (pages 45-56).
Ramírez Rancaño 1977: "Elecciones presidenciales: 1920. Presidente provisional" (page 287).
Vázquez-Gómez 1997: "In the [’Plan de Agua Prieta’] Alvaro Obregón, Adolfo de la Huerta, and Plutarco Elías Calles repudiated the government of Venustiano Carranza" (page 152).
Aguilar Camín 1993: "Adolfo de la Huerta, civilian head of Aguaprietismo, was the interim president of Mexico from June 10 to December 1, 1920" (page 73).
September 5: Federal election (Obregón Salido)
Aguilar Camín 1993: The presidential elections are held on September 5, 1920 and "Alvaro Obregón won by 1,131,751 votes to 47,442 votes for his closest runner-up" (page 74).
Brandenburg 1955: "Official statistics of the 1920 election awarded Obregón 1,131,751 of a total 1,181,550 votes cast" (page 31).
Meyer 1985: Obregón wins 95% of the vote and the PLC wins most of the seats in congress (page 81).
Ramírez Rancaño 1977: "Elecciones presidenciales: 1920-1924" (page 288).
Tamayo 1991a: Discusses the election of September 5, 1920. "El triunfo de Obregón fue arrollador: obtuvo 1 millón 979 mil 801 votos, contra 47 mil 440 de su cercano competidor, el ingeniero Robles Domínguez, y otros 2 mil 356 emitidos para diversos candidatos" (page 23).
Aguilar Camín 1993: "The year 1923...marked the De la Huertista rebellion that affected half of the army" (page 77). "[The] rebellion began on December 4, 1923, and ended in March of the following year, and implied the elimination, by death, exile, or dismissal, of fifty-four generals and seven thousand soldiers" (page 84).
Brandenburg 1955: Obregón’s administration was "interrupted in 1923 by a serious armed uprising led by de la Huerta...who believed that he, rather than Plutarco Elías Calles, deserved the next presidential nomination" (page 31).
Tamayo 1991a: On July 20, 1923 Francisco (Pancho) Villa is ambushed and killed, one theory for which is that he has close ties to Adolfo de la Huerta (pages 25-26).
July 6: Federal election (Calles)
Brandenburg 1955: "Official statistics of the 1924 election awarded Plutarco Elías Calles 1,340,634 votes and Angel Flores 252,599 votes" (page 32).
Meyer 1985: "Calles obtuvo 1,230,634 votos (84%), en tanto que el general Flores recibió apenas 252,599" (page 83).
Molinar Horcasitas 1991: "(U)na vez terminada la rebelión, un general revolucionario, Angel Flores, decidió emprender el camino electoral para oponerse a la fracción hegemónica de los revolucionarios que postularon al general de confianza de Alvaro Obregón, Plutarco Elías Calles [en la elección de 1924]" (page 46)..
Ramírez Rancaño 1977: "Elecciones presidenciales: 1924-1928" (page 289).
Tamayo 1991a: "Con la derrota del delahuertismo se afirmó la llegada de Calles a la Presidencia de la República y con él dio comienzo una nueva fase del Estado Mexicano caracterizada por una mayor concentración del poder en el ejecutivo federal y una mayor centralización política" (page 31).
Taplin 1972: Plutarco Elias Calles elected July 6, 1924 (page 64).
La Botz 1995: "In 1925 the socialists of Chiapas even succeeded in electing a socialist governor. But the governor was murdered, the ranchers took back political control, and the Chiapas socialist movement was driven underground" (page 26).
Aguilar Camín 1993: [Calles] had to confront the Cristero rebellion--which he had helped to provoke--that exploded in 1926, as a sequel to the virulent dispute between the federal government and the high authorities of the Catholic church. On July 31, 1926, the practice of Catholicism was suspended in the Mexican Republic" (page 84). "[A commission of bishops] went to the Congress with a petition to rescind the laws, signed by more than two million Mexican Catholics. On September 21, 1926, the petition was rejected by Congress...Mexico then experienced...a rebellion that at one point included 50,000 men ready to fight; lasted three years (1926-1929); ignited the states of Jalisco, Michoacán, Durango, Guerrero, Colima, Nayarit, and Zacatecas; [and] cost 90,000 lives" (page 86).
Brandenburg 1955: "The principle of no re-election had been a fundamental postulate of the Revolution since 1910; nevertheless, the Constitution was amended on January 22, 1927, to permit non-immediate re-election" (page 32).
Meyer 1985: On January 22, 1927 congress modifies the constitution to allow for presidential reelection (page 83).
Tamayo 1991a: In 1927 Arnulfo R. Gómez and Francisco Serrano, two revolutionary leaders close to Obregón, lead a military uprising against his reelection and are both executed (page 32).
Brandenburg 1955: The constitution is amended on January 24, 1928 to lengthen the presidential term to six years (page 32).
July 1: Federal election (Obregón Salido)
Aguilar Camín 1993: "Obregón...had been able to get Calles to ask Congress for a constitutional amendment to allow reelection after a term...[He] had remained as the true center of power. When the elections were finally held in 1928, he won without any problem" (page 92). "As president-reelect, death surprised [Obregón] when a Catholic fanatic, José de León Toral, shot him to death during a political breakfast in the La Bombilla restaurant on Tuesday, July 17, 1928...Calles...not only decided not to run for reelection, but announced in his last presidential address to the nation the end of the era of the ‘caudillos’ and the beginning of an era of institutions. In full agreement with the army, the chambers of Congress [on November 30, 1928] named Emilio Portes Gil as provisional president for two years, who then called for special elections for the period 1930-1934" (page 74).
Kantor 1969: "The year 1928 was one of the great turning points in Mexico’s development. After Obregón was elected president, a religious fanatic assassinated him before he could take office. There was no other strong political leader to take his place except Calles, and the constitution forbade his continuing in office...Calles...refused to take the presidency...Calles undoubtedly dominated the presidents who served until 1934, but he never again took the office himself, thus greatly strengthening the idea of alternation in office" (pages 23-24).
Meyer 1985: "(S)e celebraron las elecciones para presidente y legisladores federales el 1 de julio de 1928. Obregón era el candidato único y su triunfo fue absoluto: 1,670,453 votos para él y ninguno para nadie más" (page 84).
Ramírez Rancaño 1977: "Elecciones presidenciales: 1928-1934" (page 290).
Taplin 1972: Obregón is elected July 1, 1928 and assassinated July 17. Emilio Portes Gil is appointed by congress September 25, 1928 as interim president (page 64).
Brandenburg 1955: On September 25 congress designates Emilio Portes Gil, "incumbent Minister of Government and a former obregonista governor of Tamaulipas, as Provisional President of Mexico for the term December 1,1928-February 5, 1930" (pages 32-33).
Meyer 1985: Portes Gil is elected provisional president by congress on September 25, 1928 with 277 votes for him and two abstentions (page 85).
Smith 1974: "On September 5 Calles called the generals to the national palace and endorsed Portes Gil for the presidency...On September 25 congress elected Portes Gil to the provisional presidency by a unanimous vote" (page 20).
Aguilar Camín 1993: "On December 1, 1928, Calles and a handful of his associates presented to the country a manifesto proposing the creation of the National Revolutionary Party (PNR)" (page 93).
Aguilar Camín 1993: "In March 1929, the first national convention of the new party was held in Querétaro...(T)he first presidential candidate was...Pascual Ortiz Rubio...(O)n March 3, 1929, a group of Obregonista generals and civilians started a rebellion in the North under the so-called Plan de Hermosillo, accusing...Calles..of using the PNR to keep himself in power through the nomination of Ortiz Rubio...The uprising took root in ten states" (pages 93-94). The federal army was led by Juan Andrew Almazán in Chihuahua and Lazaro Cárdenas in Jalisco, Nayarit, and Sinaloa.
Electoral reform in Mexico 1993: "Founded in 1929 by President Calles, the main goal of the National Revolutionary Party (PNR) was to create a centralized political party controlled by the president that could check the power of Mexico’s revolutionary generals in their regional strongholds and force them to resolve their conflicts within an institutional context rather than on the battlefield" (page 12).
Grayson 1994: PNR created in 1929 "to promote unity among regional military, political, and economic leaders in the aftermath of President-elect Alvaro Obregón’s assassination" (page 23).
November 17: Federal election (Ortiz Rubio / PNR)
Aguilar Camín 1993: "The elections were won by the engineer Pascual Ortiz Rubio, the first official presidential candidate of the National Revolutionary party (PNR)" (page 74). "In the elections of November 17, 1929, Ortiz Rubio had only one significant foe, Obregón’s former secretary of public education, José Vasconcelos, nominated by the National Anti-Reelection party" (page 97). "(I)n this first encounter with the electoral opposition, it was clear that the PNR was not willing to leave in the hands of the voluble voters a decision so important as who should hold power in Mexico. The official electoral figures allotted the Vasconcelistas only 110,000 votes and granted an overwhelming 2 million votes to Ortiz Rubio" (page 110).
Meyer 1985: "Los resultados oficiales fueron rechazados por los vasconcelistas, quienes los calificaron de fraudulentos...De acuerdo con los cómputos oficiales, el poco carismático Ortiz Rubio recibió más del 93% de los 2,082,106 sufragios emitidos, en tanto que a Vasconcelos, que era una figura pública de prestigio nacional e internacional...sólo se le atribuyó nacionalmente la pequeña cantidad de 110,979 votos" (page 88).
Paoli Bolio 1985: Describes the "campaña vasconcelista" (pages 134-137) and gives the official results: "1,825,732 votos (93.58%) en favor de Ortiz Rubio y 105, 655 votos (5.42%) en favor de Vasconcelos. Los vasconcelistas proclamaron que se había cometido un fraude colosal" (page 137).
Ramírez Rancaño 1977: "Elecciones presidenciales: 1929-1934" (page 291).
Smith 1974: "The election of 1930 [should say 1929] was the first of many successes for the PNR. On election day, Vasconcelos said, the New York press printed the news of the Ortiz Rubio victory before the polls closed. On November 28 the congress decreed an Ortiz Rubio win of suspiciously large proportions: 1,948,848 to 110, 979 for Vasconcelos. Triana received 23,279 votes" (page 44).
Taplin 1972: Pascual Ortiz Rubio elected November 17, 1929 (page 64).
Smith 1974: "The PNR...won all lesser campaigns during Manuel Pérez Treviño’s first party presidency [March 1929-February 1930]; it was, in fact invariably successful. The government party won all elections for national and state offices including local deputies in [eleven states] and governors in Coahuila, México, Nayarit and Yucatán" (pages 44-45).
Fernández Christlieb 1986: "Los principales partidos pre-PNR fueron debilitados y divididos, obligados a afiliarse al nuevo partido u obligados a desaparecer si se oponían a éste. En las elecciones del 6 de julio de 1930 para el Congreso federal ni un solo candidato de oposición ganó una curul" (page 18). "
Smith 1974: "In the July 6, 1930 election the party [PNR] won every contest, of course, including races for two governorships, local deputies in ten states, fifty-six senators and one hundred and fifty-three deputies for the Thirty-fourth Legislature" (page 59).
Paoli Bolio 1985: "El 15 de octubre de  fue designado presidente del PNR el general Lázaro Cárdenas, que era por entonces gobernador de Michoacán" (page 137).
Aguilar Camín 1993: "Ortiz Rubio...was forced to resign after his differences with the strongman of the period, Plutarco Elías Calles, made his government untenable....[His] resignation before Congress, on September 2, 1932, gave way to the last interim president in Mexico’s contemporary history, the Sonorense businessman and general, Abelardo Rodríguez, who was designated unanimously by Congress to govern from September 3, 1932 to December 1, 1934" (page 74)." "Calles’s power reached its climax at that time, and the so-called Maximato its highest point" (page 98).
Smith 1974: On September 3 "the party’s [PNR] senate and chamber blocs met jointly and elected Rodríguez by acclamation. On September 4 congress unanimously elected Rodríguez substitute president" (page 71).
Meyer 1985: In March 1933 the constitution was amended to allow for no reelection of president or governors (page 89).
Smith 1974: "The PNR’s Second Ordinary Convention...began in Querétaro’s Republic Theatre on December 3, 1934 [should say 1933] with 2,000 delegates, incluidng every state governor" (page 92). "Because the party’s nomination primaries often had been marred by fraud and violence, the assembly replaced the primary system with a system of conventions. Henceforth, local conventions would nominate candidates for municipal administrations; district conventions would choose the party’s nominees for state and federal deputies, the state conventions for governors and senators. The national convention, of course, continued to nominate presidential candidates" (page 95).
July 1: Federal election (Cárdenas del Rio / PNR)
Aguilar Camín 1993: "Cárdenas was declared the winner with an incredible 98 percent of the vote" (page 147).
Meyer 1985: Gives number of votes for each presidential candidate (page 92).
Paoli Bolio 1985: "Además del general Cárdenas, hubo otros tres candidatos con poca fuerza...El general Cárdenas obtuvo dos millones y cuarto de votos (98.19%)" (page 139). Also gives the names of other candidates and percent of the vote they obtained.
Ramírez Rancaño 1977: "Elecciones presidenciales: 1934-1940" (page 292).
Smith 1974: "The more centralized PNR that followed the Querétaro convention easily won the July 1, 1934 elections...The CEN [’comité ejecutivo nacional’ of PNR] headed by Riva Palacio also won all seats in the national congress, all seats in the fifteen state legislative elections and both gubernatorial elections of the year" (page 96).
Aguilar Camín 1993: "In April 1936, accused of hoarding arms, [Calles] had to present himself to the authorities, and had to leave the country for a political and personal exile that would last almost a decade. Before Callismo could react, the Maximato had ended, and the Cárdenas era had begun" (page 131).
La Botz 1995: "Cárdenas intervened in Chiapas in 1936 supporting reformer Efraín A. Gutiérrez for governor against the local landlords’ candidate. Gutiérrez won, and his election opened the way for Cárdenas’s agrarian reform in Chiapas" (page 27).
Aguilar Camín 1993: On March 18, 1938 "Cárdenas informed the country of his decision to...expropriate the oil companies" (page 153).
Electoral reform in Mexico 1993: "In 1938, President Lazaro Cárdenas reorganized the PNR as the Mexican Revolutionary Party (PRM) under corporatist lines with separate sectors being created for labor, the peasantry, the military, and middle class groups" (page 12).
Grayson 1994: Cárdenas renames the PNR the PRM and divides it into four sectors: agrarian/peasant, labor, popular/white collar, and military (page 23).
Gorvin 1989: "The conservative PAN, formed in 1939, is the leading conservative opposition party in Mexico. It was the leading opposition party until the 1988 elections when it was overtaken by the left-wing National Democratic Front" (page 227).
Grayson 1994: PAN is founded in 1939 "as a pro-Catholic, pro-business party opposed to the nationalization, land distribution, and pro-worker policies of Cárdenas" (page 24).
Electoral reform in Mexico 1993: "By 1940, the power of the military in Mexican politics had eroded so much that the military wing of the PRM was abolished" (page 12).
July 7: Federal election (Ávila Camacho / PRM)
Aguilar Camín 1993: "Of all the groups opposing Cárdenas and his candidate, the most effective and dangerous was the group headed by General Almazán..., organized around the National Unification Revolutionary party (PRUN)" (page 157).
Meyer 1985:"Las elecciones del 7 de julio de 1940 volvieron a estar marcadas por la violencia y el robo de urnas por ambas partes...Según las cifras oficiales, de los 2,637,582 sufragios válidos, prácticamente el 94% correspondió a Ávila Camacho" (page 96).
Michaels 1971: "The year 1940 stands as an important watershed in Mexican history. In that year power passed to moderates within the Mexican revolutionary establishment who then directed the Revolution towards the more conservative path that has been followed by every subsequent Mexican government" (page 1). Describes in great detail the campaign and election of 1940.
Needler 1995: "Portes Gil is on record as saying that he convinced Cárdenas that even if Almazán received an electoral majority, the official count of votes should declare Avila Camacho the winner, since otherwise the coalition behind Almazán would destroy the achievements of the Revolution. In the event, Avila Camacho did receive a majority of votes, on the order of 75 percent, although Almazán probably carried the Federal District. In any case, a fraudulent result was announced that gave Avila Camacho 93.9 percent of the vote total...The election of 1940 marks a watershed in Mexican politics...: Almazán’s candidacy was the last in which the losing forces at least planned a revolt and Avila Camacho was the last general to be elected president of Mexico" (pages 15-16).
Paoli Bolio 1985: Describes the "conflicto almazanista" (pages 140-145) and gives the official results of the election: "La votación, según las cifras oficiales, fue la siguiente: Ávila Camacho, 2,476,641 (93.89%) y Almazán 151,101 (5.72%)" (page 145).
Ramírez Rancaño 1977: "Elecciones presidenciales: 1940-1946" (page 293).
Smith 1974: "The election day, July 7, 1940, proved one of the bloodiest in Mexican history...The Almazán forces refused to submit their ballots for tabulation, and as a result, Ávila Camacho won by a wide margin. On July 12 Jara’s CCE [’Comité Central Ejecutivo’] announced 2,265,199 votes fo Ávila Camaco, 128,574 for Almazán" (page 168).
Taplin 1972: Manuel Avila Camacho elected July 7, 1940 (page 65).
Smith 1974: "Although the PRM candidates won all seats [in the 1943 congressional election], the party was hotly contested in some districts. PAN, Bassols’ Political Action, the Communist Party and the ‘sinarquistas’ Party of Popular Force all entered candidates for the chamber of deputies" (page 184). "On July 8 the ‘juntas computadores’ informed [the president of the PRM] that his party’s candidates had won all congressional seats. The electoral college concurred, and on August 28 the CCE announced its satisfaction with the election results. The PRM had won all federal and state-wide elections and the overwhelming majority of the local contests" (pages 184-185).
Smith 1974: "Mexicans whose ideology and interests were not represented in the party and Mexicans who lost party nominations complained loudly about imposition. ‘Sinarquistas,’ for example, bitterly resisted PRM impositions in the mayoralty elections of 1945. Some 50 people were killed and 150 wounded when fighting broke out over the installation of a PRM-backed mayor in the ‘sinarquista’ stronghold of León, Guanajuato. The governor of the state removed the imposed mayor and Ávila Camacho then removed the governor" (pages 187-188).
Electoral reform in Mexico 1993: "In 1946, the PRM was redefined as the Institutional Revolutionary Party (PRI), signalling a shift from the radical changes of the Cárdenas years toward political stability and economic development" (page 12).
Levy and Székely 1987: The federal electoral law approved in 1946 "included provisions giving the government and the party absolute control over the electoral process" (page 65). Gives details of the law.
July 7: Federal election (Alemán Valdés / PRI)
Aguilar Camín 1993: "The official count was 77.9 percent for Alemán and only 19.33 percent for Padilla" (page 180).
Ramírez Rancaño 1977: "Elecciones presidenciales: 1946-1952" (page 294).
Reyna 1985: Describes 1946 election, gives total votes, and percent for Padilla (pages 102-105).
Taplin 1972: Miguel Alemán elected July 7, 1946 (page 65).
Craig and Cornelius 1995: "In 1947, women were given the right to vote and to be elected in municipal elections" (page 252).
Butler 1991: "The PPS was first organized in 1948 by left wing dissidents from the PRI. However, except for 1952 and 1988, the PPS has supported the PRI candidate for president" (page 8).
González Madrid 1995: "[El PPS] nació como Partido Popular (PP) el 20 de junio de 1948, bajo la dirección de uno de los más importantes líderes sindicales y políticos de México: Vicente Lombardo Toledano" (page 216).
Gorvin 1989: The PPS is founded in 1948 (page 227).