Why did Mexico sever diplomatic relations with the Holy See after the 1860s?

Mexico severed diplomatic relations with the Holy See in the late 1860s as a direct consequence of the government's commitment to anticlerical policies and the formal separation of church and state.1

Following the La Reforma movement, which sought to abolish colonial-era ecclesiastical privileges and reduce the church's economic and political power, the Mexican government under Benito Juárez implemented sweeping reforms. These included the confiscation of church property, the secularization of education and marriage, and the removal of special clerical courts. These actions created deep-seated tensions between the state and the religious hierarchy, leading to the eventual rupture of diplomatic ties with the Vatican. This state of severed relations persisted until 1992, when diplomatic ties were formally resumed.21