Joint Declarations are issued on behalf of Catholics, by the hierarchy. They decide the content.
Those who assist the hierarchy in this work are the Church’s best minds in those fields from which they are pressed into service by the Successors of the Apostles.
The Successors of the Apostles decide for all the Faithful and they speak for all the Faithful.
It is to be remembered that the Church proclaimed Martin Luther as Witness of Jesus Christ in 1983, on the occasion of Martin Luther’s 500th birthday.
To know for what purpose the initiatives exist, read the declaration published by the Holy See – From Conflict to Communion. It explains the matter quite clearly
And remember also what Unitatis Redintegratio articulated – the Conciliar teaching of the Pope and all the world’s Catholic Bishops:
Moreover, some and even very many of the significant elements and endowments which together go to build up and give life to the Church itself, can exist outside the visible boundaries of the Catholic Church: the written word of God; the life of grace; faith, hope and charity, with the other interior gifts of the Holy Spirit, and visible elements too. All of these, which come from Christ and lead back to Christ, belong by right to the one Church of Christ.
The brethren divided from us also use many liturgical actions of the Christian religion. These most certainly can truly engender a life of grace in ways that vary according to the condition of each Church or Community. These liturgical actions must be regarded as capable of giving access to the community of salvation.
It follows that the separated Churches and Communities as such, though we believe them to be deficient in some respects, have been by no means deprived of significance and importance in the mystery of salvation. For the Spirit of Christ has not refrained from using them as means of salvation which derive their efficacy from the very fullness of grace and truth entrusted to the Church.
All of this is certainly most true of the Lutherans.
I would pay tribute to the American bishops and to their periti who have done so much in this year of joint commemoration with our Lutheran sisters and brothers in Christ. I am pleased that, early on, they decided that the Church in America will prolong the commemorative events.
It was a blessing that, in my position, I had the opportunity myself to co-preside beside a Lutheran cleric at one of the Joint Services of Common Prayer, using the liturgy co-promulgated for this purpose by the Holy See.
It was a great privilege extended to me, for in most cases, the Cardinals and Bishops reserved to themselves the historic opportunity to co-preside with their Lutheran counterpart. Looking back to when I was a young priest, I could scarcely have imagined how much we would progress in a mere 50 years, so as to jointly commemorate the 500th anniversary of the Reformation.