Just to add a bit of information to Ed Brayton's excellent post. I agree that George Washington and John Adams were religious accommodationists, as opposed to strict separationists like Jefferson and Madison. However, one bit of information needs to be added to a quotation of Washington's that Brayton reproduced to put it in context. Washington and Adams, though accommodationists, nonetheless believed that all men of all religions (or no religions) possessed equal religious rights. In other words, they believed, contra Jefferson and Madison, that government could both at once support a particular kind of religion (i.e., Christianity) and not violate the rights of non-Christians. But they were concerned with the rights of non-Christians.
Washington's attitude towards accommodation was remarkably liberal for his time:
I must confess, that I am not amongst the number of those who are so much alarmed at the thoughts of making people pay towards the support of that which they profess, if of the denomination of Christians; or declare themselves Jews, Mahomitans or otherwise, and thereby obtain proper relief. As the matter now stands, I wish an assessment had never been agitated, and as it has gone so far, that the Bill could die an easy death;... [My emphasis.]