Edwin Gaustad posted a short essay entitled Roger Williams & Church-State Separation over at the Oxford University Press Blog (which any discriminating blogger will immediately add to their blogroll — where else will you find posts like The Year in Geography?). Roger Williams often gets overlooked in the bubbling pageant of American religious history, especially by Mormon readers who often have a hard time seeing anything of consequence in the historical record before 1830. Gaustad's essay (he also authored a recent biography of Williams) reminds us what a courageous figure was Williams, truly a man before his time. I'm also going to use this to resurrect my dormant online essay of the week feature.
The only thing I disagree with in the essay is his holding out church-state separation as some sort of public policy shibboleth. It is invoked most frequently by those who see some denomination doing something they don't like; it is conveniently ignored by anyone who sees some denomination doing something they approve of. Furthermore, the term is often thrown around by secularists as if it is the law of the land, when in fact "Congress shall make no law respecting the establishment of religion" is a much different thing. Furthermore, the United States did not even attempt to practice church-state separation until the second half of the 20th century. Before that, informal (i.e., unacknowledged) Protestant establishment was the social reality of Americna society. I'm not sure what lesson should be drawn from that, except that those who hold out America as the great experiment in church-state separation (and I'm not suggesting Gaustad is doing this in his essay) are often ignorant of that history. People who ought to know better often don't.
He ends with "Separation of church and state is a cause, not a cliché." It think it has become both a cause and a cliché, a dangerous combination.
PS: If the topic really interests you, you might look up Gaustad's books on the subject: Proclaim Liberty Throughout the Land: A History of Church and State in America (OUP, 2003), or even Church and State in America (OUP, 2d ed., 2003).