"The Bible is not my book nor Christianity my profession. I could never give assent to the long, complicated statements of Christian dogma."
- Abraham Lincoln, American president (1809-1865). Nobody knows for sure. As the above quote shows, Lincoln certainly didn't consider himself to be a Christian. But he may have held other views which would exclude him from atheism. He never said that he did so, and repeatedly referred to Christianity is poor tems. But I don't think there are any cast iron quotes which would exclude all religious belief.