It was historically a movement of the Roman Catholic extreme right, similar to clerical fascism and Falangism, implacably opposed to the policies of the Institutional Revolutionary Party (PRI) and its predecessors that governed Mexico from 1929 to 2000 and from 2012 to 2018.

It was a revival of the Catholic reaction that drove the Cristero War (that ended in 1929), and its core was centred in the Bajío rural bourgeoisie and professional lower middle-class, where Catholicism was very strong.

[22] The UNS was led by Salvador Abascal, a hard-liner, from 1940 to 1941 when he stood down in order to set up a synarchist commune in Baja California with the more moderate Manuel Torres Bueno becoming leader.

[24] President Manuel Ávila Camacho placed a ban on the UNS holding public meetings in June 1944 at a time when factionalism was dividing the movement.

[37][38] The ideology of the UNS derived from the clerical fascism that was a strand of Catholic social thinking of the 1920s and 1930s,[7] based on the papal encyclical Rerum novarum of Pope Leo XIII, which also influenced the regimes of Engelbert Dollfuss in Austria, António de Oliveira Salazar in Portugal and Francisco Franco in Spain.

Instead, they saw the echoes of New Spain as the "fertile medieval period in which our races were united in intimate communion with the majesty of the Catholic God," and independence, with the exclusion of the First Mexican Empire, as a process of national decline.

On the other hand, Catholicism was the fundamental core of the Synarchist program and sought the destruction of the liberal order to emphasize the return to the "glorious Hispanic, Greco-Latin, and Christian tradition," considering communism and Americanism as threats to its cultural heritage.

The movement's distancing from fascism did not reduce its misgivings about U.S. governments, and while they emphasized formal neutrality in World War II, they would see a greater threat in U.S. imperialism.

The movement made no secret of its sympathies for authoritarian regimes that governed along similar ideological lines, such as those of António de Oliveira Salazar, Francisco Franco, and Juan Domingo Perón, and opposed the "treacherous forces" that loomed over the countries, such as freemasonry and political parties, and aimed to forge closer ties with similar movements in other countries to "establish throughout the world the Order of Christ."

Embracing its autonomy and denying the influence of European fascist movements, although imitating them in appearance and sharing anti-capitalist and anti-communist foundations, Synarchism would have from its inception a powerful current in favor of the nationalist faction during the Spanish Civil War and the Francoist Spain.

Salvador Abascal highlighted his sympathy for the "broad and working class spirit" of José Antonio Primo de Rivera, who led the Spanish Falange of the Councils of the National Syndicalist Offensive, but stated that he did not implant any of his ideas in the movement.

In the Synarchist discourse, Jews were one of the social groups considered "enemies of the fatherland," and they emphasized Bolshevism and capitalism as doctrines and tendencies that wanted to undermine the Christian tradition in confluence with Judaism.

Despite the fact that the Jewish population in Mexico was relatively small, Synarchist leaders deemed the Judeo-Masonic conspiracy thesis to be valid and stressed the threat Jews posed to Christianity.

It is important to note that the United States played a role of influence and pressure on Synarchism to eliminate the radicalism of Salvador Abascal and to seek a less intransigent leadership, since the UNS represented a stumbling block for U.S. external policy.

The expansion of Synarchism and its embedded anti-American discourse threatened the interests of the foreign government, leading to Abascal's ousting from the leadership in December 1941 and a partial reorientation of the movement's activity towards a pro-American stance.

Notwithstanding this, Synarchists would strongly oppose Mexico's participation in World War II, and the radical sector of the organization would persist in upholding the traditional principles of the UNS, claiming Abascal's leading role in the movement.

It would persist as such throughout the 1950s until its ideological conversion to Christian Democracy, which would provoke a significant number of old-school militants, including the writer and historian Celerino Salmerón.