The Holocaust was the product not of Christendom, but of Christendom's collapse. The destruction of Christendom effected (1) the rejection of Catholic natural law and (2) the rise of the absolute nation-state, previously impossible because popes could depose and counterbalance kings. Hitler, to be sure, contributed a neo-paganism and anti-Semitism all his own. But in mobilizing opinion and wielding power, he was helped more by these two innovations than by any Catholic doctrines.

Jesus, Jews and the Shoah: A Moral Reckoning by Daniel Jonah Goldhagen (2003)