"Well, I am not quite sure what the Apostolic Constitution has to do with the Great Commission..."
So wrote Bishop Brian Marsh of the ACA's Diocese of the Northeast. Is it any surprise then that he sees no conflict between actively seeking some kind of merger with another Continuing Anglican body that has no desire to seek unity with the Catholic Church, and still maintain some vague interest in Anglicanorum Coetibus? The Apostolic Constitution, according to Bishop Marsh, "is a document only. We will never find unity in a document alone."
Further confusion follows when Bishop Marsh tries to water down Christian unity to some kind of bare minimum, (and divorcing it from a proper sacramental economy) thus appealing to Richard Hooker for support:
Richard Hooker, the great Anglican divine [sic], once wrote that, when we are baptized in the Name of the Father, the Son and Holy Ghost, we are already unified spiritually. Consider that; all who profess the faith of Christ crucified and who believe in the Trinity are already in unity. Unity has happened; it already exists. That was unity for Richard Hooker, one of the great Anglican theologians [sic]. He identified precisely the Anglican way of unity. And the simple formula he calls attention to includes most Christians in the known universe. Over a billion of us. In spiritual unity. [emphasis mine]
For an explanation of how a TAC bishop under the Portsmouth Statement could then say something seemingly contradictory, appealing to "the Anglican way", see: Dispensing With the Branch Theory. Notice the use of the old tactic of separating juridical unity from sacramental communion. Juridical unity does not, of course, mean one monolithic corporate church body, as if only the Latin Rite were the entirety of the Catholic Church. It does mean, however, that the myriad of bodies must be subject to the same Pontiff if they are to be in communion with him. There is also a shared canon law. There is mutual episcopal recognition of temporal and geographic jurisdiction by other rites (churches). This is how both the Orthodox and Catholic churches have always understood it. The Orthodox don't pretend to be spiritually unified with the Pope while maintaining how sad it is that they are not in communion with him and still juridically separated. To do so would fly in the face of the two-thousand year old understanding of what schism and communion actually are.
In addition, to separate the unity we find in baptism from the further unity we find in the other six sacraments, as well as the juridical authority of bishops in communion with the Apostolic See, is to attempt to divide the indivisible. Ironically, this is the mistake that the Episcopal Church made; they tried to elevate the understanding of baptism beyond being the sacrament of regeneration and initiation. While it is true that by our baptism we have a share in the life of the Catholic Church (for it is the Church's sacrament), it is not all that is required. It's the beginning of a process. Archbishop Michael Ramsey explains this well in his book, The Gospel and the Catholic Church. It was Hans Urs von Balthasar who wrote about the Church, being the Body of Christ, mirroring Christ's own two natures. Just as Christ is completely man and completely God, so too is the Church physical and spiritual. It is physical in that juridically it is united in tangible ways. It is spiritual in that all those jurisdictions are in communion with each other, with the Vicar of Christ on earth, and of course with Christ himself.
I won't speculate on personal motivations on the part of the three bishops, but a theological justification for unity with the Anglican Province of America (APA) after signing the Portsmouth Statement and signing of the Catechism of the Catholic Church to signify agreement, requires a later redefinition of terms from what the Portsmouth Statement and Catechism intend and, of course, how the Roman Catholics to whom it was addressed would naturally understand those terms. Of course, if the three bishops do not believe they redefined the terms after the fact to make the terms fit the Branch Theory's understanding of them, then it means that they either never actually read the Catechism or they never really understood what it meant as the Catholic Church means it.
So if ignorance, rather than dishonesty, was the case, one wonders why these three even bothered to sign it (or be consecrated after the signing--for the TAC's canons require all bishops to act collegially) until they properly understood it on Rome's terms rather than on their own? For after all, it was Rome to whom they were writing.
Now back to Bishop Marsh's statement: "I am not quite sure what the Apostolic Constitution has to do with the Great Commission." Well, Pope Benedict has the answer.