I found the following video from EWTN very informative. It discusses how many of today's evangelicals think of themselves as "born-again" Christians. In John 3, Jesus instructs Nicodemus on the necessity of being "born again" in order to enter the Kingdom of Heaven. Yet the Bible is one thick ass book and there, all sorts of things are said by Jesus and OTHER "inspired" writers and speakers on requirements for entering the Kingdom of Heaven.
For instance, in Matthew 18:3, Jesus says, “Truly, I say to you, unless you turn and become like children, you will never enter the kingdom of heaven.”
Yet, there is no "become like children-Christian" movement like there is a "born-again Christian" movement. Yet, there is the same TEXTUAL support for BOTH kinds of Christianities. In, say, the year 2500, one could imagine such a movement.
Apparently Luther and Calvin, though they were "Protestant," "Reformed," "orthodox-Trinitarian," were not "born-again Christians," at least they did not preach being "born again" as an ELEMENT for when one becomes a "real" or "regenerate" Christian. Rather, they held to infant-baptismal regeneration, like the Roman Catholics.
Update: At my home blog my friend Ron comments:
Jon, although I no longer consider myself a Christian (in any conventional sense), as a Unitarian Universalist I've always identified with the term "radical protestant." To me, it represents a shift of authority (in assessment of truth) from a "top down" model (whether an infallible Church or State or infallible scripture) to more of a "bottom-up" paradigm of ultimate self-discernment of truth and meaning.
To me, being part of this "radically left wing of the Protestant Reformation" tradition in religion means that my spiritual ancestors were so stubbornly protestant that they increasingly refused to let anyone else (in any age, no matter how highly esteemed) do their thinking for them. It means that I can draw an identifiable line from the Minor Reformed Church of Poland (Socinians) to kindred spirits of freedom-inspired religion in the present day (whatever the title).
I would suggest that, to us, the term protestant is more about methodology than theology, not so much about particular beliefs as the approach used to determining those beliefs. (As I've commented elsewhere, if the name hadn't already been taken, UU's could have been called "methodists" in reference to their stubbornly protestant attitude applied even to matters of religion.)