The gulf I have in mind was brought to the forefront of my mind when Susan Lim, a reputable Christian historian at Biola recently wrote an article about religion and the Founding Fathers for Christianity Today. Lim wrote,
"Washington’s successor, John Adams, was born into a devout Christian family and raised to carry on Puritan traditions. The second president of the United States never wavered away from his faith, nor did he ever see any conflict in being both an independent thinker and committed Christian. As David McCullough recounts in his Pulitzer Prize-winning biography, Adams regularly boasted of his Puritan ancestry, sometimes bordered on legalism (he often refused to travel on the Sabbath), and occasionally cast stones against those he deemed less spiritual than himself. For example, Adams made it a point to highlight Jefferson’s nontraditional religious convictions when they both vied for the presidency."
This surprised me, because I believed it was fairly well established that Adams was basically a U/unitarian (did not believe in the Trinity) unlike the Puritans, though he may have remained in Puritan Congregationalist churches. I wrote the following email to Susan (actually, I emailed "Dr. Lim" who graciously told me to call her Susan):
"I have no doubt that Adams was a man of faith and may have valued his Puritan heritage, but it seems to me that we have it pretty decisively in his own words that he was a Unitarian and (perhaps a bit more ambiguously) that he also had serious reservations about the incarnation. I appreciate the fact that there is some disagreement on this, but it mostly seems to come from American Filiopietists with political agendas. I'm not sure how you say that he "was born into a devout Christian family and raised to carry on Puritan traditions. The second president of the United States never wavered away from his faith, nor did he ever see any conflict in being both an independent thinker and committed Christian." I guess I can sort of spin this in a way, but I think it is liable to mislead many readers."
Susan responded: "No doubt, the term "Puritan" is a messy one. I shy away from it in my research. I used it here because I assume that the majority of the readers aren't academics, and the term "Congregational" won't resonate with as many readers. Puritanism has come to mean so many things to so many people; and as I'm sure you know, many of the social constructs of Puritanism were made in the 19th C (largely through fiction) to comment on Victorian society (by using Puritans as actors). Or, as Mencken wrote, that Puritanism is thought of as the haunting fear that someone, somewhere may be happy. Of course we know that this obviously doesn't do the Puritans justice. What I meant was that John Adams hailed from a Puritan/Congregational family, and remained committed to his Congregational church. Yes, that church (along with many other Congregationalist churches) moved towards Unitarianism by the mid-18th C, but I didn't want to go into the development of Congregationalism (or Puritanism, if you will) here."
Note that if this is true, Adams was in the advance guard of a group of Puritan Congregationalists who rejected the the doctrine of the Trinity that had defined Christian Orthodoxy for around 1400 years. At the time, many/most U/unitarians did consider themselves Christians and their services of worship would have resembled Trinitarian Puritans' services a great deal. Susan Lim is a knowledgeable scholar. She also possesses the virtue of inclusion in her approach to John Adams and Christianity (something many contemporary Christians could learn from). I don't believe she was trying to fool anyone. However, I still think this way of writing about things plays into the hands of those who have a political agenda and are also much sloppier in their characterizations of the faith of the founders.
The point is that in the "translation" process that most historians use when writing for a popular audience (and, keep in mind that many popular writers are also writing history without the benefit of education in the discipline), a great deal of the nuances are left out.
To review some of the complications about this, check out this post from the American Creation blog, and then read this one. It might be worthwhile looking at some of the comments as well.