Irreligion in Mexico

Irreligion in Mexico refers to atheism, deism, religious skepticism, secularism, and secular humanism in Mexican society, which was a confessional state after independence from Imperial Spain. The first political constitution of the Mexican United States enacted in 1824, stipulated that Roman Catholicism was the national religion in perpetuity, and prohibited any other religion. Moreover, since 1857, by law, Mexico has had no official religion; as such, anti-clerical laws meant to promote a secular society, contained in the 1857 Constitution of Mexico and in the 1917 Constitution of Mexico limited the participation in civil life of Roman Catholic organizations, and allowed government intervention to religious participation in politics.
In 1992, the Mexican constitution was amended to eliminate the restrictions, and granted legal status to religious organizations, limited property rights, voting rights to ministers, and allowing a greater number of priests in Mexico. Nonetheless, the principles of the Separation of Church and State remain; members of religious orders (priests, nuns, ministers, "et al.") cannot hold elected office, the federal government cannot subsidize any religious organization, and religious orders, and their officers, cannot teach in the public school system.
Historically, the Roman Catholic Church dominated the religious, political, and cultural landscapes of the nation; yet, the Catholic News Agency said that there exists a great, secular community of atheists, intellectuals and irreligious people, reaching 10% according to recent polls by religious agencies.
According to world population studies, 78% of the Mexican population believe in God and 22% do not believe in him. In addition to the fact that it is estimated that 36% of the Mexican population considers themselves non-religious. 
Thus, 22% of the Mexican population considers themselves atheist, agnostic or non-believing and 36% as non-religious giving a total that 58% of the Mexican population is irreligious.
Religion and politics.
Since the Spanish Conquest (1519–21), the Roman Catholic Church has held prominent social and political positions concerning the moral education of Mexicans; the ways that virtues and morals are to be socially implemented; and thus contributed to the Mexican cultural identity. Such cultural immanence was confirmed in the nation's first political constitution, which formally protected Catholicism; thus, Article 3 of the 1824 Constitution of Mexico established that:
For most of Mexico's 300 years as the Imperial Spanish colony of the Viceroyalty of New Spain (1519–1821), the Roman Catholic Church was an active political actor in colonial politics. In the early period of the Mexican nation, the vast wealth and great political influence of the Church spurred a powerful anti-clerical movement, which found political expression in the Liberal party. Yet, during the middle of the 19th century, there were reforms limiting the political power of the Mexican Catholic Church. In response, the Church supported seditious Conservative rebels to overthrow the anti-clerical Liberal government of President Benito Juárez; and so welcomed the anti-Juárez French intervention in Mexico (1861), which established the military occupation of Mexico by the Second French Empire, of Emperor Napoleon III.
About the Mexican perspective of the actions of the Roman Catholic Church, the Mexican Labour Party activist Robert Haberman said:
At the turn of the 19th century, the collaboration of the Mexican Catholic Church with the "Porfiriato", the 35-year dictatorship of General Porfirio Díaz, earned the Mexican clergy the ideological enmity of the revolutionary victors of the Mexican Revolution (1910–20); thus, the Mexican Constitution of 1917 legislated severe social and political, economic and cultural restrictions upon the Catholic Church in the Republic of Mexico. Historically, the 1917 Mexican Constitution was the first political constitution to explicitly legislate the social and civil rights of the people; and served as constitutional model for the Weimar Constitution of 1919 and the Russian Constitution of 1918. Nevertheless, like the Spanish Constitution of 1931, it has been characterized as being hostile to religion.
The Constitution of 1917 proscribed the Catholic clergy from working as teachers and as instructors in public and private schools; established State control over the internal matters of the Mexican Catholic Church; nationalized all Church property; proscribed religious orders; forbade the presence in Mexico of foreign-born priests; granted each state of the Mexican republic the power to limit the number of, and to eliminate, priests in its territory; disenfranchised priests of the civil rights to vote, and to hold elected office; banned Catholic organizations that advocated public policy; forbade religious publications from editorial commentary about public policy; proscribed the clergy from wearing clerical garb in public; and voided the right to trial of any Mexican citizen who violated anti-clerical laws.
During the Mexican Revolution (1910–20), the national rancour provoked by the history of the Catholic Church's mistreatment of Mexicans was aggravated by the collaboration of the Mexican High Clergy with the pro–U.S. dictatorship (1913–14) of General Victoriano Huerta, "The Usurper" of the Mexican Presidency; thus, anti-clerical laws were integral to the Mexican Constitution of 1917, in order to establish a secular society. In the 1920s, the enforcement of the Constitutional anti-clerical laws, by the Mexican Federal Government, provoked the Cristero Rebellion (1926–29), the clerically-abetted armed revolt of Catholic peasants, known as "The Christers" ("Los cristeros"). The social and political tensions between the Catholic Church and the Mexican State lessened after 1940, but the Constitutional restrictions remained the law of the land, although their enforcement became progressively lax. The Government established diplomatic relations with the Holy See during the administration of President Carlos Salinas de Gortari (1988–94), and the Government lifted almost all restrictions on the Catholic Church in 1992. That year the Government ratified its informal policy of not enforcing most legal controls on religious groups by, among other things, granting religious groups legal status, conceding them limited property rights, and lifting restrictions on the number of priests in the country. However, the law continues to mandate strict restrictions on the church and bars the clergy from holding public office, advocating partisan political views, supporting political candidates, or opposing the laws or institutions of the State. The Church's ability to own and operate mass media is also limited. Indeed, after the creation of the Constitution the Catholic Church has been acutely hostile towards the Mexican government. As Laura Randall in his book "Changing Structure of Mexico" points out, most of the conflicts between citizens and religious leaders lie in the Church's overwhelming lack of understanding of the role of the state's laicism. "The inability of the Mexican Catholic Episcopate to understand the modern world translates into a distorted conception of the secular world and the lay state. Evidently, perceiving the state as anti-religious (or rather, anti-clerical) is the result of 19th-century struggles that imbued the state with anti-religious and anti-clerical tinges in Latin American countries, much to the Catholic Church's chagrin. Defining laicist education as a 'secular religion' that is also 'imposed and intolerant' is the clearest evidence of episcopal intransigence." Others, however see the Mexican state's anticlericalism differently. Recent President Vicente Fox stated, "After 1917, Mexico was led by anti-Catholic Freemasons who tried to evoke the anticlerical spirit of popular indigenous President Benito Juárez of the 1880s. But the military dictators of the 1920s were a more savage lot than Juarez." Fox goes on to recount how priests were killed for trying to perform the sacraments, altars were desecrated by soldiers and freedom of religion outlawed by generals.
Demographics.
As many students of Latin American religion have pointed out, there is a substantial difference between describing oneself as religious or culturally religious and practicing one's faith literally. In the case of Mexico the decline of the church's religious influence is specially mirrored by the decline of church attendance among its citizens. Church attendance itself is a complex, multi-layered phenomenon that is subject to political and socio-economic factors. From 1940 to 1960 about 70% of Mexican Catholics attended church weekly while in 1982 only 54 percent partook of Mass once a week or more, and 21 percent claimed monthly attendance. Recent surveys have shown that only around 3% of Catholics attend church daily; however, 47% percent of them attend church services weekly and, according to INEGI, the number of atheists grows annually by 5.2%, while the number of Catholics grows by 1.7%.