The Argumentum ad Constaninem doesn’t explain why the Oriental Orthodox and Assyrian Church of the East remain so close to Catholicism despite the fact they broke with Rome in rebellion against Constantine’s successors.
The Constantine folks seem to forget that his immediate successors persecuted people like St. Athanasius for his orthodox confession of faith.
Perhaps the Evangelicals who bash Constantine are closet Arians. :)
The Oriental Orthodox broke with Rome in 451 about 125 years after Constantine.
And the Assyrian Church of the East broke with Rome in 431.
Yet they believe in everything that Evangelicals hate the Roman Catholic Church for save Roman supremacy and the scholastic interpretation of purgatory.
(I might note that the scholastic interpretation of purgatory isn’t a dogma of the Catholic Church because Eastern Catholics are not required to teach it.)
I think that it is a lot worse than that and they are not in the closet. The Presbyterians are the latest...