In his letter, the Holy Father writes about some mistakes made both with regard to the decision itself, especially in light of Williamson's extreme and unreconstructed view of our elder brothers in the faith, which his faux and rightly rejected quasi-apology hardly changed, and as regards the clear communication as to what exactly was the extent of the Holy See's action.
In his letter to his brother bishops, the Bishop of Rome writes:
"An unforeseen mishap for me was the fact that the Williamson case came on top of the remission of the excommunication. The discreet gesture of mercy towards four Bishops ordained validly but not legitimately suddenly appeared as something completely different: as the repudiation of reconciliation between Christians and Jews, and thus as the reversal of what the Council had laid down in this regard to guide the Church’s path.Closer to the end of the letter, Pope Benedict writes:
"A gesture of reconciliation with an ecclesial group engaged in a process of separation thus turned into its very antithesis: an apparent step backwards with regard to all the steps of reconciliation between Christians and Jews taken since the Council – steps which my own work as a theologian had sought from the beginning to take part in and support.
"That this overlapping of two opposed processes took place and momentarily upset peace between Christians and Jews, as well as peace within the Church, is something which I can only deeply deplore. I have been told that consulting the information available on the internet would have made it possible to perceive the problem early on. I have learned the lesson that in the future in the Holy See we will have to pay greater attention to that source of news. I was saddened by the fact that even Catholics who, after all, might have had a better knowledge of the situation, thought they had to attack me with open hostility. Precisely for this reason I thank all the more our Jewish friends, who quickly helped to clear up the misunderstanding and to restore the atmosphere of friendship and trust which – as in the days of Pope John Paul II – has also existed throughout my pontificate and, thank God, continues to exist.
"Another mistake, which I deeply regret, is the fact that the extent and limits of the provision of 21 January 2009 were not clearly and adequately explained at the moment of its publication."
"Dear Brothers, during the days when I first had the idea of writing this letter, by chance, during a visit to the Roman Seminary, I had to interpret and comment on Galatians 5:13-15. I was surprised at the directness with which that passage speaks to us about the present moment: 'Do not use your freedom as an opportunity for the flesh, but through love be servants of one another. For the whole law is fulfilled in one word: "You shall love your neighbour as yourself". But if you bite and devour one another, take heed that you are not consumed by one another.'
"I am always tempted to see these words as another of the rhetorical excesses which we occasionally find in Saint Paul. To some extent that may also be the case. But sad to say, this 'biting and devouring' also exists in the Church today, as expression of a poorly understood freedom. Should we be surprised that we too are no better than the Galatians? That at the very least we are threatened by the same temptations? That we must always learn anew the proper use of freedom? And that we must always learn anew the supreme priority, which is love? "
UPDATE 1908 MDT: Rocco over at Whispers reports on what is likely to happen in the wake of all this.