"I would disagree in saying that the French Enlightenment (Volatire, Diderot...) was the birthplace of Secularism not Darwin. And they did have a primary influence on the writing of the Constitution."
I would have to disagree with you about the timing of 'Secularism's' beginning with the French, although plenty can be laid at their doorstep, Secularism got its first planting in the Garden of Eden. The serpent (devil)whispered sweet seductions into Eve's ear telling her that, 'God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil.' That planting is with us to this day.