Warren Throckmorton has more on Metaxas & Barton

Here and here. Here is a taste from the first link:

You remember 2012 right? American University prof and author Jay Richards recruited 10 Christian historians to read David Barton’s book on Thomas Jefferson (The Jefferson Lies, the one just recommended by Metaxas) and then read my book with Michael Coulter Getting Jefferson Right which was a response to Barton’s. Richards asked those scholars to render a verdict about the accuracy of the books and our book came out on top. Do you recall that Thomas Nelson heard from critics of Barton’s book and did their own review? Then after the review by the 10 scholars and the publisher, Thomas Nelson announced that it was pulling the book from the shelves due to historical inaccuracies. Remember that historian Thomas Kidd documented all of this for World magazine? All of that happened.

Jay Richards, I don't believe works for American University, but Catholic University. Daniel Dreisbach works for American University.

That's a minor note of correction. The above passage is important. Most of these historians and right leaning and want to challenge the view in law, history and politics that limits the expression of religion in public life.

Barton is making that side look bad and hurting their credibility.