Especially when combined with the intensely scholarly tradition of the Jews, it is almost impossible to overstate the impact on the world of the Jewish denial of Original Sin, and of unfulfilled Jewish Messianic hope and expectation.
The former may not necessarily have originated, but has certainly contributed immeasurably, to the concept of the perfectibility of human nature in this life alone and by human efforts alone. Thus was the latter able to give the world Marx and Trotsky, Freud and Alinksy, Max Shachtman and Leo Strauss, Milton Friedman and Ludwig von Mises, Zionism and the secular Turkish ultranationalism that goes back to the Donmeh (the ultimate in unfulfilled Jewish Messianic hope and expectation). This list is far from exhaustive.
However radically, each of these is completed, perfected and transformed by, in, through and as the Messiah. As much as anything else, He necessarily turns them away from any purely temporal utopianism, a radical transformation indeed for most or all of them.
Or else they become neoconservatism, a compendium of all of them, and the ultimate expression of the theory, utterly horrific in the consequences at which it always arrives eventually, that human nature can be perfected in this life alone and by its own efforts alone, since Jesus of Nazareth is not the Messiah promised by and to the Hebrew Prophets.