I don't have a problem with people being Christian, especially the Christian Left. I do have a problem when Christians try to change history in order to support their beliefs. That's why I've been so interested in those who claim the Founders created this to be a Christian nation and they had no intention of creating a wall of separation between Church and State. The people who promote this view do so in order to argue that therefore Christianity - at least their version of it - deserves special treatment by the federal, state, and local governments of the United States.
The problem is that the Christian nation types LIE about history in order to make it conform to their views. The person doing the most to counter their lies is Chris Rodda, author of the book Liars for Jesus. The book is long, dry, and gets into history in more detail than even I want, and I have two degrees in history. But it requires that level of detail to show the problem areas of the Christian Nation types. When I bought the book, I thought the title was too harsh, and so did the minister who wrote the forward to the book. But after I read it, I had to agree with Rodda. The things the Christian Nation writers said couldn't be just errors and bad scholarship. They were too closely edited for that to be the case.
Anyway, I found out about Chris Rodda from Ed Brayton's blog Dispatches from the Culture Wars. In this blog post from Ed, he posts 9 snippets of video from Chris Rodda specifically refuting David Barton, the best known of the Christian Nation writers. In the first video she explains why he is so important - he is extremely influential in fundamentalist Christian circles, including writing the American history textbooks often used in Christian schools and home schools. Here she refutes some of his claims. She's dry in person, too, but she's damn good at what she does.