In a widely expected yet still critically important move, Pope Benedict XVI has tapped Bishop Gerhard Ludwig Müller of Regensburg, Germany, to succeed American Cardinal William Levada as Prefect of the powerful Congregation for the Doctrine of the Faith.

Among other things, the appointment means that Müller, 64, will be the key Vatican player in the overhaul of the Leadership Conference of Women Religious demanded by the doctrinal congregation in April.

Some observers believe the fact that the exchange with LCWR will now be led by a non-American may affect the intensity of the congregation’s interest, if not the substance of its positions.

Levada, who turned 76 in June, had led the congregation since May 2005.t

The pope’s new doctrinal czar has a profile in Germany as a staunch defender of Catholic orthodoxy, yet not an ideologue. Among other things, Müller has a strong friendship with Peruvian liberation theologian Gustavo Guttierez.

Müller clearly enjoys the pope’s confidence.

Aside from the fact that Müller is the bishop of the pope’s home diocese, where Benedict’s brother Geörg still resides, he’s also the editor of Benedict’s “Opera Omnia,” a comprehensive collection of all the pope’s theological writings. Müller himself is a prolific author, having written more than 400 works on a wide variety of theological topics.

Despite his broadly conservative reputation, Müller actually earned his doctorate in 1977 under then-Fr. Karl Lehmann, who went on to become the cardinal of Mainz and the leader of the moderate wing of the German bishops’ conference. Müller’s dissertation was on the famed German Protestant theologian Dietrich Bonhoeffer.

Moreover, Müller is also a close personal friend of Guttierez, widely seen as the father of the liberation theology movement in Latin America. Every year since 1998, Müller has travelled to Peru to take a course from Guttierez, and has spent time living with farmers in a rural parish near the border with Bolivia.

In 2008, he accepted an honorary doctorate from the Pontifical Catholic University of Peru, which is widely seen as a bastion of the progressive wing of the Peruvian church. On the occasion, he praised Guttierez and defended his theology.

“The theology of Gustavo Gutiérrez, independently of how you look at it, is orthodox because it is orthopractic,” he said. “It teaches us the correct way of acting in a Christian fashion since it comes from true faith.”

Müller has been rumored to be in pole position to take over at the doctrinal congregation for some time, and late last year there was a push in traditionalist circles to try to block the appointment. E-mails were circulated suggesting that Müller, already a member of the Congregation for the Doctrine of the Faith, is not a man of “secure doctrine.”

Specifically, the e-mails cited Müller for espousing suspect positions on the virginity of Mary (which he said in a 2003 book shouldn’t be understood in a “physiological” sense), the Eucharist (Müller has apparently counseled against using the term “body and blood of Christ” to describe the consecrated bread and wine at Mass), and ecumenism (last October, Müller declared that Protestants are “already part of the church” founded by Christ.)

Defenders of Müller argued that in each case, his words had either been taken out of context or were consistent with official teaching.

Yesterday, a leader of the traditionalist Catholic Society of St. Pius X objected to Müller's appointment, citing his allegedly heterodox views on the perpetural virginity of Mary.

"It is not acceptable that the leader of the congregation holds a heresy," said Auxiliary Bishop Alfonso de Galarreta, one of four prelates in the breakaway society.

The comments came in a ceremony in which de Galarreta ordained two new priests for the society.

One of Müller's new responsibilities will be managing negotiations with the Society of St. Pius X. The Vatican recently announced plans for a personal prelature, meaning a non-territorial diocese, to reincorporate traditionalists wishing to return to communion with Rome.