I guess it is starting now.
Remember, the Great Depression took place when America had one of the best educated, most literate, cultured and gentlemanly civilizations in the history of the world. People back then had stable extended family structures, Christian faith and tolerance, a feeling of collective unity and the knowledge that all your neighbors were people like you, with the same values and roughly the same characters and paradigms for life.
It's 2008. Today it's an ethnically fragmented multiracial polyglot that barely holds together in the best of times thanks to the perpetual threat of armed force by a seemingly all-powerful government.
I say one spark and that dynamite dump will blow sky-high. It'll be a 3000 mile long flaming Balkans from the East to the West coast.
I predict a couple of years in that environment trying to survive and the hardest of hardcore atheists will pine with nostalgic tears for the days when America was just a bunch of kindly, sweet goofy white European Christians wishing well from sunup to sundown. A couple of months of running from naked machete wielding cannibal diversity pals will sway even the most rabid of secularists over to the virtues of a strong Christian religious ethic for a society. They won't care in the least anymore about some petty argument over some parcel of scripture that reads funny to them at the end of Leviticus. With perspective they will realize what they have lost and it is a terrible loss indeed.