For over a thousand years, questioning the Trinity was punishable by excommunication, torture, or death. Arius, who taught that the Son was subordinate to the Father (a position far closer to Scripture), was branded a heretic. Michael Servetus, who rejected the Trinity on biblical grounds, was burned at the stake in 1553 — with John Calvin's approval. The doctrine was not protected because Scripture demanded it. It was protected because institutional power had been built on top of it.
The Catholic Church Enforces Trinitarian Orthodoxy
Dissent is labeled heresy. For over a thousand years, questioning the Trinity was punishable by excommunication, torture, or death.