After Pope Francis early in his papacy decried capitalism as “trickle-down economics” — a polemical phrase coined by the left during the Reagan years that Francis frequently borrows — radio talk show host Rush Limbaugh commented, “This is just pure Marxism coming out of the mouth of the Pope.” Talk show host Michael Savage called him “Lenin’s pope.” Pope Francis took such comments as a compliment. “I have met many Marxists in my life who are good people, so I don’t feel offended,” he told the Italian press.

Pope Francis grew up in socialist Argentina, an experience that left a deep impression on his thinking. He told the Latin American journalists Javier Camara and Sebastian Pfaffen that as a young man he “read books of the Communist Party that my boss in the laboratory gave me” and that “there was a period where I would wait anxiously for the newspaper La Vanguardia, which was not allowed to be sold with the other newspapers and was brought to us by the socialist militants.”

The “boss” to whom Pope Francis referred is Esther Ballestrino de Careaga. He has described her as a “Paraguayan woman” and a “fervent communist.” He considers her one of his most important mentors. “I owe a huge amount to that great woman,” he has said, saying that she “taught me so much about politics.” (He worked for her as an assistant at Hickethier-Bachmann Laboratory in Buenos Aires.)

“She often read Communist Party texts to me and gave them to me to read. So I also got to know that very materialistic conception. I remember that she also gave me the statement from the American Communists in defense of the Rosenbergs, who had been sentenced to death,” he has said. Learning about communism, he said, “through a courageous and honest person was helpful. I realized a few things, an aspect of the social, which I then found in the social doctrine of the Church.” As the archbishop of Buenos Aires, he took pride in helping her hide the family’s Marxist literature from the authorities who were investigating her. According to the author James Carroll, Bergoglio smuggled her communist books, including Marx’s Das Kapital, into a “Jesuit library.”

“Tragically, Ballestrino herself ‘disappeared’ at the hands of security forces in 1977,” reported Vatican correspondent John Allen. “Almost three decades later, when her remains were discovered and identified, Bergoglio gave permission for her to be buried in the garden of a Buenos Aires church called Santa Cruz, the spot where she had been abducted. Her daughter requested that her mother and several other women be buried there because ‘it was the last place they had been as free people.’ Despite knowing full well that Ballestrino was not a believing Catholic, the future pope readily consented.”

These biographical details throw light on the pope’s ideological instincts. Yet many commentators have ignored them, breezily casting his leftism as a bit confused but basically harmless.

“I must say that communists have stolen our flag. The flag of the poor is Christian,” he said in 2014. Such a comment would have startled his predecessors. They didn’t see communism as a benign exaggeration. They saw it as a grave threat to God-given freedom, as it proposes that governments eliminate large swaths of individual freedom, private property and business in order to produce the “equality” of a society without economic classes.

In the early twentieth century, as Marx’s socialism spread across the world, Pope Pius XI declared the theory anathema. “No one can be at the same time a good Catholic and a true socialist,” he said. To hear Pope Francis speak today, one might conclude the reverse: that no can be at the same time a good Catholic and an opponent of socialism.

“Inequality is the root of all evil,” Pope Francis wrote on his Twitter account in 2014. One can imagine Karl Marx blurting that out, but none of Francis’s predecessors would have made such an outrageous claim. According to traditional Catholic theology, the root of all evil came not from inequality but from Satan’s refusal to accept inequality. Out of envy of God’s superiority, Satan rebelled. He could not bear his lesser status.

He was in effect the first revolutionary, which is why the socialist agitator Saul Alinsky — a mentor to Barack Obama and Hillary Clinton (who did her senior thesis at Wellesley on his thought) — offered an “acknowledgment” in his book, Rules for Radicals, to Satan. Alinsky saw him as the first champion of the “have nots.”

Were the 20th-century English Catholic satirist Evelyn Waugh alive today, he would find the radical left-wing political flirtations of Pope Francis too bitterly farcical even for fiction. Could a satirist like Waugh have imagined a pope happily receiving from a Latin American despot the “gift” of a crucifix shaped in the form of a Marxist hammer and sickle? That surreal scene happened during Pope Francis’s visit to Bolivia in July 2015.

Evo Morales, Bolivia’s proudly Marxist president, offered the pontiff that sacrilegious image of Jesus Christ. Morales described the gift as a copy of a crucifix designed by a late priest, Fr. Luis Espinal, who belonged to the Jesuit order (as does Pope Francis) and had committed his life to melding Marxism with religion. Pope Francis had honored Espinal’s memory upon his arrival in Bolivia.

Had John Paul II or Pope Benedict XVI seen such a grotesque cross, they might have broken it over their knees. Not Pope Francis. He accepted the hammer-and-sickle cross warmly, telling the press on the plane ride back to Rome that “I understand this work” and that “for me it wasn’t an offense.” After the visit, Morales gushed, “I feel like now I have a Pope. I didn’t feel that before.”

George Neumayr is the author of The Political Pope: How Pope Francis Is Delighting the Liberal Left and Abandoning Conservatives, to be released Tuesday by Center Street.