This is from DAVID D. KIRKPATRICK, 2005. It's very good, quite fair to both sides. They got Mark Noll to go on record on David Barton. Here's a taste:
But academic historians, including some conservative and evangelical scholars, give the Christian conservative veneration of this history about a B-minus. They say that Mr. Barton is more or less right, as far as it goes, that the founders never guessed that courts would construe the First Amendment to forbid public displays of religion like prayer in the schools. But the 18th-century religious views of the founders hardly fit into contemporary categories like evangelical Protestant or secular humanist. Nor, historians say, do the great leaders' public expressions of faith necessarily tell us much about how their notion of an ideal relationship between religion and government.
"Barton is a very hard-working researcher, but what I guess I worry about is the collapsing of historical distance, and the effort to make really anybody fit directly into the category of the early 21st century evangelicals," said Mark A. Noll, a prominent historian at Wheaton College, a prestigious evangelical school.
But, Professor Noll added, "I would say he is no worse than some of the Ivy League types who do the same thing, who say the founding fathers believed in separation of church and state and therefore we do, too."
Gordon Wood, a professor at Brown and historian of early America, agreed that the founders never imagined a culture as secular as ours. After all, many states had tax-supported churches well into the 19th century. "They definitely did not contemplate this kind of what we might call 'extreme,' where a minister or a rabbi at a public school graduation is considered to be a violation of separation of church and state," Professor Wood said. "We have built that wall much higher than any of them, even Jefferson, would have anticipated."
But he said educated colonials like the founders also took a dim view of religious fervor. "They just were not in favor of religious 'enthusiasms' - that is the word they would have used for what we would call evangelical," he said.
Richard Brookhiser, a biographer of Washington and a senior editor at the conservative National Review, put it differently. "The temperature of a lot of 18th century religion was just a lot lower," he said.