SPIEGEL: What is currently happening at the Vatican is what you spent your life fighting for: a liberalization and reform of the church. This is happening at a time when you are becoming old and feeble. Is it an irony of history?
Küng: The irony is more applicable to my former colleague (Joseph) Ratzinger than to me. I did not expect to see a radical shift in the Catholic Church in my lifetime. I had always assumed -- and had come to accept -- that Küng would depart and Ratzinger would remain. That's why I was so surprised to see Benedict go and Pope Francis assume office on March 19, 2013, my birthday and Ratzinger's name day.
SPIEGEL: How could it happen that a college of cardinals made up of conservative and generally backward-looking men elected a revolutionary to be the next pope?
Küng: First of all, they didn't even know how revolutionary he is. But aside from the hard core of the Curia, many cardinals knew that the church is in a deep crisis, which is epitomized by corruption in the Vatican, the cover-up of abuse cases and the Vatileaks scandal. The cardinals were often confronted with tough criticism by their home congregations.
SPIEGEL: Can one person even revolutionize an institution like the Catholic Church?
Küng: Yes, if he receives good advice as pope and has a capable staff. Legally speaking, the pope has more power than the president of the United States.
SPIEGEL: But only within the church, because, for example, his decisions are not subject to the approval of a legislative body.
Küng: There is also no supreme court. If he wanted to, the pope could immediately abolish the celibacy law introduced in the 12th century.
SPIEGEL: Could the Arab Spring be followed by a Catholic Spring?
Küng: It's already here, but there is the same risk of setbacks and counter-movements as there have been with the Arab Spring. There are powerful groups in the Vatican and the church around the world that would like to turn back the clock. They're worried about their privileges.
SPIEGEL: Does it bother you that you can no longer get involved in these debates?
Küng: I take it calmly. It's more important to me that the pope reads what I send him than that he invites me to Rome.
SPIEGEL: He recently wrote to you that he likes reading the two books you sent him, and that he remains "at your disposal."
Küng: I have already received two handwritten and very friendly letters from him. The return addresses on the envelopes simply read "F., Domus Sanctae Marthae, Vaticano," and he signed the letters "with brotherly greetings." Even that is a new style. In 27 years, John Paul II didn't deem me worthy of a single response.
SPIEGEL: With whom can Francis be compared?
Küng: Probably John XXIII, but he lacks one of his weaknesses. John XXIII made reforms in passing and without an agenda. He made serious administrative mistakes.
SPIEGEL: The question is whether Francis only impresses people with gestures, or whether there is more behind it than that.
Küng: The simpler clothing, the changes to the protocol and the completely different tone of voice -- these aren't just superficial things. He has introduced a paradigm shift. With this pope, we see the service character of the papal office emerging once again. He wants priests to get out of the church and encounter people. He recently sent a survey to the bishops to obtain the views of laypeople on family subjects. His first trip took him to the refugees on Lampedusa. All of this is a departure from the way in which Benedict interpreted the office. The call for a poor church also leads to a different way of thinking. Under Benedict, the extravagant bishop of Limburg would probably still be in office.
SPIEGEL: But Francis has also reconfirmed Archbishop Gerhard Ludwig Müller, a hard-liner, as head of the Congregation for the Doctrine of the Faith, the Vatican's watchdog and enforcer on issues of accepted doctrine.
Küng: I could imagine that Benedict strongly campaigned for keeping Müller in the position. But the litmus test will be whether the new pope continues to allow him to play overseer of the faith and grand inquisitor.
SPIEGEL: Francis has announced the canonization of John Paul II, a restorative pope who strengthened controversial groups such as Opus Dei and the Legion of Christ.
Küng: I cannot understand why this pope is to be canonized. He was the most contradictory pope of the 20th century. He venerated the Virgin Mary, and yet he denied women offices in the church. He preached against mass poverty, and yet he barred contraception. I discussed 11 of these massive contradictions at length in the last volume of my memoirs. His words constantly diverged from his actions. For instance, he considered the priest Marcial Maciel, one of the worst molesters of boys and the founder of the Legion of Christ, to be his personal friend and defended him against all criticism.
SPIEGEL: And yet you forgive Francis for this canonization?
Küng: Benedict expedited Wojtyla's canonization, ignoring all required waiting periods. Stopping the process now would not only be an affront to Benedict, but also to many Poles. I can understand that Francis doesn't want to do that. At least he also announced the canonization of reformist Pope John XXIII. We should also think about whether canonizations, which are an invention of the Middle Ages, still make sense today.