As an ally of Calles, Obregón was hated by Catholics and was assassinated in a restaurant on 17 July 1928, shortly after his return to Mexico City, by José de León Toral, a Roman Catholic opposed to the government's policies on religious matters.

Calles was allowed to return to Mexico under the reconciliation policy of Cárdenas's successor Manuel Ávila Camacho in 1941.

The Plan of Agua Prieta, was a political manifesto signed in the city of Agua Prieta, 23 April 1920 by the governor of Sonora ( which is part of the population ) Adolfo de la Huerta and Plutarco Elías Calles, in support of Álvaro Obregón, the principal object to obtain termination of the presidency of the Republic of Venustiano Carranza.

Calles founded several banks in support of campesinos as well as the Banco de México, Mexico's national bank.

By the summer of 1933, two of old wartime subordinates of Calles had risen to the top of the party: Manuel Pérez Treviño and Lázaro Cárdenas Calles sought to have Trevino be the party's nominee at the time, seeing that he would be the most likely to continue his policies, but soon caved into pressure from party officials and agreed to support the popular land reformer Cárdenas as the PNR's presidential candidate in the 1934 Mexican Presidential election.

With their support Cárdenas had Calles and Morones arrested and deported that year.

Obregón's successor, Emilio Portes Gil – a forced ally of Calles due to the upheaval created by Obregón's assassination – fired CROM officials from their government posts and threw the government's support to rival union groups, such as the Confederación General de Trabajadores, ( CGT ), a nominally anarchist group, and the Confederación Sindical Unitaria de México, a group associated with the Mexican Communist Party ( PCM ).

When President Lázaro Cárdenas del Río called on unions for support in resisting a threatened coup by Calles and opposing an employers ' strike in Monterrey, the CGOCM and the PCM rallied to his defense.

The CGOCM and the Mexican Communist Party ( PCM ) rallied to support President Cárdenas when he called on unions for support in resisting a threat of coup by former president Plutarco Elías Calles, and in opposing an employers ' strike in Monterrey.

Plutarco Calles, at the center of power for the anti-clerics, continued to gather power in Mexico City.

In 1923, Obregón endorsed Plutarco Elías Calles for president in the 1924 election ( in which Obregón was not eligible to run ).

The 1924 Calles presidential campaign was the first populist presidential campaign in the nation's history, as he called for land redistribution and promised equal justice, more education, additional labor rights, and democratic governance.

Calles is most noted for a fierce oppression of Catholics that led to the Cristero War, a civil war between Catholic rebels and government forces, and for founding the Partido Nacional Revolucionario ( National Revolutionary Party, or PNR ), which eventually became the Institutional Revolutionary Party ( PRI ) – which governed Mexico for more than 70 consecutive years.

On 28 May 1926, Calles was awarded a medal of merit from the head of Mexico's Scottish rite of Freemasonry for his actions against the Catholics.

The internal political dissension became a concern for all Mexicans since the regulations imposed by Calles reduced the Catholic Church's influence.

In 1926, following passage of stringent anti-clerical criminal laws and enforcement of these so-called Calles Laws ( named for President of Mexico Plutarco Elias Calles ) coupled with farmer's revolts against land reform in the heavily Catholic Bajio, scattered guerrilla operations coalesced into a serious armed revolt against the government.

In June 1926 he signed the " Law for Reforming the Penal Code ", known unofficially as the " Calles Law ".

Unlike his predecessors, he vigorously enforced the anti-Catholic provisions of the 1917 constitution, implementing the so-called " Calles Law ", which provided specific penalties for priests who criticized the government ( five years imprisonment ) or wore clerical garb in certain situations outside their churches ( 500 pesos ).

President Calles gave orders to have Pro executed under the pretext of the assassination, but in reality for defying the virtual outlawing of Catholicism.

The vast majority are Roman Catholic priests who were executed for carrying out their ministry despite the suppression under the anti-clerical laws of Plutarco Elías Calles.

When President Plutarco Elías Calles pushed for the creation of the ‘ Mexican Apostolic Catholic Church ’, independent of Rome, it unleashed a widespread religious war known as the Cristero War.

The political crisis deepened when Calles launched a series of verbal attacks on Cárdenas that amounted to a call for his overthrow.

Its course is interrupted by several reservoirs like Plutarco Elías Calles ( El Novillo ), Lázaro Cárdenas ( Angostura ), or Álvaro Obregón ( El Oviáchic, Lake Ouiachic ), which provides the water resource for the intensively irrigated region of Ciudad Obregón.

The conspirators drafted Adolfo de la Huerta, then-Minister of Finance, to run for president against Plutarco Elias Calles, Obregón's chosen successor.

Calles used his ability to draw in labor class votes to come to power with Obregón.

Calles ' presidency was supported by labor and peasant unions.

Calles had once been the candidate of the workers and at one point had used Communist unions in his campaign against competing labor organizers but later, having acquired wealth and engaging in finance, suppressed Communism.

Freedom of worship was no longer suppressed, although some states still refused to repeal Calles ' policy, and relations with the church improved while Cardenas was president.

In May 1927, while General Obregón seemed keen to impose the presidency to General Calles, General Arnulfo R. Gómez launched a military coup against both Obregón and Calles.

Though the now strongly conservative Calles thought he could control him, it quickly became clear Cárdenas would not accept a subordinate role like his predecessors did.

After establishing himself in the presidency, in 1936 Cárdenas had Calles and dozens of his corrupt associates arrested or deported to the United States.

He backed Plutarco Elías Calles, and after Calles became president, Cárdenas became governor of Michoacán in 1928.

Instead they selected Cárdenas to be the ruling party's presidential candidate, and Calles went along with it, thinking he could control him as he had the previous two.

After establishing himself in the presidency, Cárdenas and the Mexican Congress turned on Calles and condemned his continued war-like persecution of the Catholic Church.

In 1936, Cárdenas had Calles and twenty of his corrupt associates arrested and deported to the United States, a decision that was greeted with great enthusiasm by the majority of the Mexican public.

The CTM and Toledano in turn supported Cárdenas ' deportation of ex-President Calles.

Plutarco Elías Calles and Lázaro Cárdenas, two future presidents of Mexico, both lived in the town during its early years.

Because Cárdenas had long been associated with Calles since he joined his army in Sonora in 1915, he was trusted by the callistas and Calles was under the false assumption he could control Cárdenas as he had controlled his predecessors.

Soon after his inauguration, however, conflicts between Calles and Cárdenas started to arise.

Cárdenas started to isolate Calles politically, removing the callistas from political posts and exiling his most powerful allies: Tomás Garrido Canabal, Fausto Topete, Emilio Portes Gil, Saturnino Cedillo, Aarón Sáenz and finally Calles himself.

Calles and Luis Napoleón Morones, one of the last remaining influential callistas and onetime Minister of Agriculture, were charged with conspiring to blow up a railroad and placed under arrest under the order of President Cárdenas.

For example, Lázaro Cárdenas turned against and exiled Calles to the United States and Joaquín Balaguer was elected to the Dominican presidency six times after the assassination of Trujillo.

" Calles ' military persecution of Catholics would be officially condemned by left-socialist leaning President Lázaro Cárdenas and the Mexican Congress in 1935.

As it was mentioned above, the Calles law was repealed after Lázaro Cárdenas became president.