Here is an interesting article from a magazine published by "Americans United for the Separation of Church and State". It goes into the history of Christian support of slavery, Jim Crow laws, oppression of Native Americans, gays, religious minorities, etc.

https://www.au.org/church-state/june-2015-church-state/viewpoint/an-evangelicals-lament

Here are articles on related issues that "Americans United..." is dealing with:

https://www.au.org/church-state/june-2015-church-state/au-bulletin/tenn-bill-to-make-the-bible-its-official-book-fails

https://www.au.org/church-state/june-2015-church-state/people-events/baptist-minister-slams-religious-right-for

Note that the executive director of "Americans United..." is an ordained minister in the United Church of Christ.