It is impossible to have a purely secular political system where religion does not play an important role. Ideas do not come from vacuums. They have a source of inspiration. There are only two available sources of inspiration; God's and Satan's. So when nations are run by elected officials and politicians who lie because their only goal is a pathway to riches, that can never be by divine inspiration and that society is on a downward spiral toward destruction.
Benjamin Franklin Morris' book has been out of print for more than 100 years. If you can find an original copy, it's only because you have looked in the deep recesses of university libraries where the volume is probably collecting dust on dimly lit library shelves. Organizations like the ACLU and Americans United for Separation of Church and State have done their best to ignore the content of the massive compilation of original source material found in this book. If Americans ever become aware of the content assembled by the author, the arguments for a secular founding of America will turn to dust.