The Society of Saint Pius X (SSPX), whose four bishops were readmitted to the Church last year after a ban of 21 years, cannot conduct the doctrinal discussions on their terms, but only on those of the Vatican, Cardinal Walter Kasper said.
The closed-door talks are a key issue for the Catholic Church because, although the SSPX is small, its return to the fold has been so stormy. One readmitted bishop, Richard Williamson, is a Holocaust denier convicted and fined for hate speech in Germany.
Pope Benedict's eagerness to rehabilitate the SSPX, despite its rejection of the Second Vatican Council (1962-1965) reforms, troubles Catholic critics who see them as anti-Semites who want to turn back the clock on 40 years of dialogue among religions.
"Dialogue with them is not easy," Kasper, who heads the Vatican department for relations with other Christian churches and with Jews, told a news conference during a visit to Paris.
"The main problem with them is not the Mass in Latin," he said, referring to the SSPX's insistence on the pre-Council liturgy, "but the concept of tradition. Do we want a living tradition or a petrified one?"
"I'm for a dialogue, but on our conditions, not on the traditionalists' conditions," he added. The SSPX had to accept the Council reforms, the "sine qua non" of any accord.
Without an accord, the group will have no official status and its clergy will not be recognised as Catholic priests or allowed to exercise their ministry.
Benedict, who has promoted a return to Catholic tradition and identity during his five-year papacy, said in January that the talks among three theologians from each side were held up over "doctrinal problems" he did not specify.
The SSPX, numbering several hundred thousand members, insists it represents the true faith and the Vatican and the vast majority of the Church went off the rails at the Council.
POPE'S SLEEPLESS NIGHTS
Even while its theologians meet Vatican experts every other week to seek a common understanding of the Council, its leaders have been criticising key doctrines of that historic event.
SSPX head Bishop Bernard Fellay said in March the Vatican theologians "wish the Church well but also want to save the Second Vatican Council -- that's like squaring a circle."
Williamson, ignoring a gag order Fellay imposed on him after his interview denying the Holocaust, dismissed the Vatican talks in January as a futile bid to harmonise irreconcilable views.
"Either the SSPX becomes a traitor, or Rome converts, or it's a dialogue of the deaf," he said.
In recent months, the SSPX head in Germany has criticised Benedict for visiting the Rome synagogue and the French district head said dialogue with other faiths was ruining the Church.
A former colleague, German theologian Wolfgang Beinert, told Der Spiegel magazine last month that the pope had told him the SSPX issue "robs him of his sleep." He did not think Benedict would compromise at any cost with the ultra-traditionalists.
Kasper, the second-highest German at the Vatican after Benedict, said the SSPX has staunchly opposed the dialogue with other Christian churches for which he is responsible.
"They've attacked me as a heretic," he said with a smile.
Asked why the ultra-traditionalists opposed ecumenical dialogue so strongly, he said: "Some people feel threatened in their Catholic identity when we speak with Protestants.
"We need to have a Catholic identity," he said. "But we need an open and mature identity, not a closed one. That's not a mature identity."
SIC: RIND