An organization of committed lay Catholics is challenging Democratic vice presidential nominee Tim Kaine, who’s invoking his Catholic faith and the words of Pope Francis as a basis for his radical positions on abortion and marriage, as well as his embrace of liberation theology.

Brian Burch of CatholicVote says faithful Catholic voters and leaders deserve to know the truth about Hillary Clinton’s running mate, and how the time he spent in Honduras – which he has referenced as a “turning point in my life” – helped to shape both his political and religious views.

In a memo, Burch writes that Kaine took a leave of absence from Harvard Law School in 1980 for his “mission trip” to Honduras to work with Jesuit missionaries. The memo continues:

During his stay in Honduras, Kaine openly embraced liberation theology, a controversial political ideology cloaked in Catholic teaching, but radically at odds with the Catholic Church and with the United States. At the time, this extremist ideology was adopted by activists and even some clergy who were openly hostile to the Church, the Pope, and the United States. The Marxist elements of this ideology were condemned by the Vatican in the 1980’s and 1990’s. During his time in Latin America, Kaine was surrounded by radicals and their influences took root in the version of Christianity he adopted. According to the New York Times, it was this theology that set him on a “left-veering career path” influencing his politics to the present day.

The memo recounts Kaine’s relationship in Honduras with radical liberation theology proponent Father James Carney, who accepted “armed rebellion, socialism, Marxism, and communism” as part of God’s plan for political and social change. Prior to his death as a member of the Sandinista rebel army, Carney helped found socialist broadcast outlet Radio Progresso.

Kaine continues to be in touch with Carney’s successor, Father Ismael Moreno Coto (Father Melo), and announced in a press release in November of 2014 that he met with the Jesuit priest.

“I think of El Progreso every day,” Kaine said. “The people, aside from my family, are the most important in shaping who I am today.”

Though he touts his “Catholic” faith, Kaine has consistently voted in favor of abortion rights, and recently told LGBT activists that the Catholic Church’s opposition to same-sex marriage would eventually change since God sees all of Creation as “very good,” including homosexuality.

In its memo, CatholicVote says, “Pope John Paul II, Pope Benedict XVI, and Pope Francis have all opposed the radical Marxist nature of liberation theology.”

“In 2005, Pope Francis (then Cardinal Bergoglio) noted that ‘liberation theology’ and ‘Christian Socialism’ (Carney’s preferred category) had survived by ‘inertia’ even if some ‘anachronistically’ want to resurrect it,” the memo continues. “Perhaps most succinctly, Pope Benedict called it the theology of ‘Barabbas’ as opposed to that of Jesus Christ.”