Socialism and
communism in
Catholic social teaching had been already addressed in the teachings of popes since the
encyclicals
Nostis et nobiscum (1849),
Quanta cura (1864), and
Rerum novarum (1891). Interpretations of these encyclicals and the stance towards socialism expressed in them varied. Catholic journalist
G. K. Chesterton, who formulated
distributism based on his interpretation of
Rerum Novarum, believed that the Catholic encyclicals condemned socialism and postulated an alternative economic system that would be neither capitalist nor socialist. Others, like
Eugène-Melchior de Vogüé, argued that the papal encyclicals only constituted a condemnation of some, anti-clerical, forms of socialism. British philosopher
Andrew Collier believed that Chesterton misinterpreted
Rerum Novarum as the Catholic argument against socialism, and instead interpreted
Rerum Novarum as an argument for
Catholic socialism, arguing that "the aim of
Rerum Novarum can only be achieved via Marxist methods". After revolutions in Russia, China, and Mexico had been followed by religious persecution, a new theme of criticism was added, beginning with
Quadragesimo anno (1931) by
Pope Pius XI. This encyclical objected to what it considered to be communism's professed opposition to religion, and its threat to the freedom and the very existence of the Church. On July 15, 1948, ''
L'Osservatore Romano'' published a decree which excommunicated those who propagate "the materialistic and anti-Christian teachings of Communism". The document, however, did not mention the
Italian Communist Party, which had changed its statutes in 1946, removing an explicit profession of
Marxism-Leninism, and opening to participation by citizens, "independent of race, religious faith or philosophical convictions". In the spring of 1949, pressure on the Church in Czechoslovakia was increasing, and, according to Cardinal
Giovanni Battista Montini, then papal Secretary of State, Pope Pius XII, had come to feel that there would be no effective diplomatic opposition from the West. Thus, the Church had to use what means it had to confront communism, not only in the immediate situation, but for a long-term opposition. ==Form of the document==