"Secular atheism" only works in very wise, intelligent and humble hands, in the sense of being aware that the interplay of religious faith and the public square has at once great benefits in some contexts, and great negativity in others. There is no grand unified theory readily at hand. If you combine "secular atheism" with hubris, you get negative results. One size does not fit all things. The planet is a complex place. JMO.
I'd have to agree there. You might be interested in Brooke Allen's new book about the founders. She's right about a lot of the details, but not always correct or temperate in her interpretations. Her animus against the "religious right" blinds her to some of the complexities and ambiguities in the founders' America and our own.
Faith and doubt, religion and irreligion aren't sufficient in themselves to govern our lives. They're tied together in a knot that one can't simply untie or sever. You can't be all faith or all skepticism but need one to temper the other. A humanistic "faith in Mankind" has the problems of other religions. In the 20th century, it was a lot more dangerous than the older religions.
All we have gained then by our unbelief
Is a life of doubt diversified by faith,
For one of faith diversified by doubt:
We called the chess-board white-we call it black.
Robert Browning
I'm not sure Browning is entirely right -- people lose much when they lose religion -- but he's captures the interdependence of belief and skepticism quite well, and the very questionable benefit of atheism.