By James Mackenzie
ROME (Reuters) - Pope Benedict on Monday appointed German bishop Gerhard Ludwig Mueller to head the Vatican office in charge of Church doctrine, one of the central bodies responsible for enforcing Church discipline at a time of exceptional upheaval.
Mueller's appointment to a powerful job the pontiff himself held for more than two decades - prefect of the Congregation for the Doctrine of the Faith - comes at a time when the Vatican is beset by controversies including allegations of corruption and internal intrigues, as well as a lingering child abuse scandal.
Mueller will have the delicate task of overseeing issues ranging from overhauling Church practice in the wake of the scandal of child sexual abuse by priests to reconciling the position of dissident ultra traditionalist movements.
The 64-year-old bishop of the southern German city of Regensburg, where the pope himself taught theology in the 1960s, is a well respected conservative theologian and the author of some 400 publications.
Unusually for a bishop elevated to high office under the conservative Benedict, he has links to the politically-tinged liberation theology movement of South America, which has been sharply criticized by both Benedict and his predecessor John Paul II.
Mueller is overseeing publication of the collected works of Joseph Ratzinger, who took the name Benedict when he became pope. But among his own publications is a work written with liberationist theologian Gustavo Gutierrez, called "On the Side of the Poor. The Theology of Liberation".
German Catholic reform group Wir sind Kirche said Mueller had a "profound knowledge" of Church doctrine and said the traditionalist tone of his best known book, "Catholic Dogmatics. For the Study and Practice of Theology" had probably determined the pope's decision to appoint him.
"Another, particularly important question will be whether his longstanding, friendly contact with South American liberation theologists, in particular with its spiritual father Gustavo Gutierrez, may lead to a new evaluation of liberation theology, which Ratzinger has fought for years," it said.
The Congregation for the Doctrine of the Faith is the main office policing doctrine and was founded in the 16th century as the Sacred Congregation of the Universal Inquisition, the notorious body charged with protecting the Church from heresy.
The role is crucial to the way the Vatican conducts itself and the appointment comes at a time when it is trying to grapple with the aftermath of a major scandal over corruption and internal intrigue following the arrest of the pontiff's butler for leaking secret documents.
Despite Mueller's connection with liberation theology, Wir sind Kirche criticized what it described as a disciplinarian style during his time in Regensburg.
"Rigorous action against reform forces was more important to him than dialogue, the inaction of Church discipline more important than changing obvious wrongs, attacking those who think differently more important than a offering the hand of reconciliation," it said.
It said he had refused to accept that structural factors within the church were a significant part of the reason for the sexual abuse scandal.
Mueller succeeds William Joseph Levada, the former bishop of San Francisco, who succeeded Benedict himself in the office when the then Cardinal Joseph Ratzinger became pope in 2005.
Levada, 76, is stepping down from the office on grounds of age, the Vatican said.
Mueller was elevated to the rank of archbishop at the same time as his appointment to head the doctrinal office, but the prefect is traditionally a cardinal, suggesting he will probably be raised to that rank at some point.
(Reporting By James Mackenzie; Editing by Barry Moody and Andrew Osborn)