Few recent actions taken by the Vatican have been as crass or damaging to the Roman Catholic Church as the Pope's decision to lift the excommunication of a bishop who has denied the Holocaust. The reaction, not surprisingly, has been explosive. The chief rabbinate of Israel has cancelled a planned meeting with Catholic officials. The head of Germany's Jewish community has also pulled out, saying she was “enraged” by the decision. The British Government and MPs from all parties have expressed incredulity. Catholics across the world have been mystified by the timing and aghast at the naivety. And the Vatican, yet again, has been forced into the humiliation of repeated apologies, exculpatory explanations and attempts to limit the damage.

A Pope raised in Hitler's Germany should have been sensitive to the implications. He has since expressed “solidarity” with Jews. He is said to have been “troubled” by the interview given by Richard Williamson in which the schismatic bishop denied that the Nazis had used gas chambers to murder Jews. This is lame stuff. The 81-year-old Pope is well educated and intelligent. Long responsible, as former Cardinal Ratzinger, for doctrinal obedience, he knows that his statements must be well researched and unambiguous. Yet, all too often during his papacy his words have caused offence: to Muslims, to Anglicans, to homosexuals and now to Jews.

Each time the Vatican has insisted that he had no such intention. That can mean only two things, both equally unfortunate: either the Pope and his entourage are unaware of the context of his remarks; or that his determination to assert Catholic doctrine overrides any constraints of tact, empathy and diplomacy that should underpin his message and win respect for his influence as a global spiritual leader.

Bishop Williamson is one of four followers of the late Archbishop Marcel Lefebvre, a conservative who fiercely opposed the Vatican's reforms of the 1960s, and was excommunicated. They particularly opposed the declaration “Nostra Aetate”, according to which Jews are the “older brothers” of Christians. The Pope decided to lift their excommunication out of “paternal mercy”, hoping apparently that this gesture to Catholic traditionalists, along with the reintroduction of the Latin Mass, would strengthen the Church in its struggle against liberal questioning of established doctrine.

Recent Vatican statements have all but halted moves towards reconciliation with Anglicans and other Protestants. Ecumenicism is clearly less important to the Pope than maintaining the unity of the Catholic Church. Bringing sectarian dissidents back into the mainstream, however, must never be at the expense of honour, justice and truth. Bishop Williamson has not been readmitted because of his odious views but despite them. But those views are too shocking and too perverse to be ignored. Indeed, voicing them today in Benedict XVI's own homeland is a crime.

The signal sent from Rome this week is appalling. It reinforces the suspicion of some Jews that Christianity still harbours latent anti-Semitism. It diminishes the Vatican's influence in the Middle East at a time of conflict. It makes the Pope appear foolish or misguided. It is a gesture that should be retracted immediately unless, and until, Bishop Williamson renounces his obscenities.