It’s the ecumenical dog that doesn’t bark. We need him to bark, but he rarely does, and then he's quickly shushed. It’s the matter of conversion. When we pray for Christian unity, as we do this week, we pray not only for kindness and fellow-feeling and some very foggy idea of joining together in the future, after a gradual convergence somewhere in the middle.
We pray for our separated brethren to give in.
The Truest Unity
For Catholics, the truest unity requires living together within the Catholic Church. As the bishops said quite plainly at the Second Vatican Council, those they called "our separated brethren" do not enjoy "that unity which Jesus Christ wished to bestow on all those who through Him were born again into one body, and with Him quickened to newness of life. ... For it is only through Christ's Catholic Church, which is 'the all-embracing means of salvation,' that they can benefit fully from the means of salvation. We believe that Our Lord entrusted all the blessings of the New Covenant to the apostolic college alone, of which Peter is the head." The dog barked then.
