Church and State: A Humanist View by Vern L. Bullough:

Here. A taste:

There have been two conflicting traditions in the United States about the relationship between church and state. The first is exemplified by the holiday of Thanksgiving, which emphasizes the religious foundation of the United States. The Pilgrim fathers set out in the New World not only to worship as they wanted but to establish God's kingdom. They had the truth and all others were wrong; church and state were one. The second tradition comes from the time of the writing of the American Constitution, when our deistic, freethinking Founding Fathers (no mothers) embodied in the Constitution the principle of separation of church and state.

The conflict between the two traditions should be obvious, and it was neatly finessed by our Constitution makers by more or less ignoring what states did. Although technically the last established religion was eliminated in 1833 in Massachusetts, the lack of an established religion did not mean real separation of church and state. States later admitted to the union had to adopt statutes about religious freedom, but, since most Americans nominally came from a European Christian background, religious observances played an important role in American history. One current example is the delivering of a prayer that opens up Congress, a practice that Free Inquiry's editor, Paul Kurtz, attempted to stop by a lawsuit, which he lost.

I was never more struck by the contradictions in our concepts of separation of church and state than when I lived in so-called emancipated New York State. I appeared several times in court in New York as an expert witness, and each time I was required to swear an oath on the Bible to tell the truth so help me God. I objected to the attorneys for whom I was testifying but they asked me not to call attention to the issue since it could negatively affect their client. I complied. In the university at which I taught in New York, the commencement ceremonies were opened and closed with prayers, although there was a real effort by the clergy doing the invocation and benediction to keep their remarks general and platitudinous. Most secular schools in the United States have Christmas and Easter breaks, although the Easter break is somewhat less common than it was a few years ago. The most secular school I attended was the University of Chicago, at one time a Baptist school, which ignored religious holidays of all kinds but did have its quarter session usually end about December 22.