Section 67 of Caritas in Veritate draws heavily from the pre-Vatican-II papal encyclical Pacem in Terris [1963]., and to a lesser extent the post-Vatican-II encyclical Populorum Progressio [1967]. In the section on the U.N. the "subsidiary" quote comes from BXVI himself, but the majority (but not all) of the "one-world-government" sounding quotes are taken Pope John XXIII's encyclical Pacem in Terris. I don't see any ambiguity in anything that's said.
I meant to say read encyclicals from pre-Vatican II popes. That would be Pius XII and before.
If Caritas in Veritate is not ambiguous, why does every published summary seem interpret the document differently, or even oppositely? I skimmed through and could not make any sense of it.
The part about “subsidiary” is good because it conflicts with “one-world-government” but that is just an example of the ambiguity.