Sorry if I misstated the Orthodox position - I always thought that the RCC was the only Church that was upfront about stating is is the one and only true Church. Yes I think it will take a miracle for serious reunification. Regarding your last line, never understood why certain Protestant don’t accept the one baptism doctrine. I think a good starting point for at least some Protestant unity would be lets just accept each others baptism. Is it really fruitful to engage in the whole infant vs adult baptism, immersion vs sprinkling debate? Is it worth dividing over?
The baptism issue is huge among Protestant denominations.
I grew up Baptist, and the issue of adult vs. infant baptism is gigantic.
You see, Baptists and other evangelical denominations do not accept sacraments. To them, baptism is an outward manifestation of an INWARD change. They believe that a person choose to be baptized out of obedience to Jesus, as a demonstration that they are CHOOSING to follow Jesus.
An infant cannot choose to follow Jesus. So an infant baptism is not valid to a Baptist. It means nothing.
Baptists and many other evangelical denominations do not accept that baptism has any “saving” power. It’s just a symbol of a decision to follow Christ.
That’s one reason why Baptists can and do accept some Catholics as Christians. To Baptists, being saved has nothing to do with baptism. If a person has made a decision to follow Christ and give their life to Him, then they are saved.
Other Protestant denominations, mainly the mainlines (Lutheran, Reformed, Presbyterian, Episcopalian, etc.) still accept the sacraments, including the sacrament of Baptism. They attach some kind of saving power to baptism.
There are subtle and not-so-subtle shades of difference in baptism doctrines among all the Protestant denominations. Some do not believe that baptism is necessary at all, and some even teach that it is a “work of man” and therefore, an abomination to the Lord Jesus. Others, e.g., the Campbellite churches (Church of Christ, Christian church, DIsciples of Christ) believe that Baptism is necessary for salvation; these “Restoration” churches are closer to Catholicism in their teaching about baptism and communion. The Reformed Churches believe that baptism brings a child (or adult) into the “covenant” and makes them part of the Church, but doesn’t necessarily save them.
I’m only listing a few that I have personal experience with. There are many others. And I haven’t even begun to touch the issue of “baptism by immersion” vs. “sprinkling and pouring.” This issue alone is a source of fierce and bitter conflict between evangelical denominations and many other denominations.
So I think that Baptism is highly unlikely to become a rallying point for unity among Protestants. IF anything, it will continue to be a controversial issue and a point of sorrowful division among Protestants.