In my experience, militant Catholics rarely claim that Catholics are in full doctrinal unity with anyone or anything... such would be ABSURD.... I know hundreds of Catholics and not two that fully agree. The CLAIM is that the singular RC denomination is "in full unity".... they just are careful to not finish the sentence, because the reality (known to all) is that the RCC is in unity with.... NONE (Well, itself...but then the LDS is in unity with itself, too - doesn't mean much). ANY self who looks in the mirror at self will see self, just not sure how one doing that makes them better than another doing that.
Now, that obvious point noted, there IS much more doctrinal unity among most Christians than I think is generally acknowledged, and the Nicene Creed is a GREAT example of that. Eastern Orthodox, Roman Catholic, Lutherans, Anglicans, Methodist, Reformed and well beyond - maybe 95% of Christians - affirm the Creed (even if they don't regularly proclaim it). And while the wording may vary slightly and our understandings differ a bit in a few places, it IS stunning how much we are all affirming. It's understandable that Christians seeking agreement focus on where the work still needs to be done (thus focus on where we disagree), it should not be forgotten that we agree on MUCH. FULL agreement? No. MUCH agreement? Yes. And that spans across MANY denominational lines.
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