Liberal & well-meaning John Rawls might have thought that "the veil of ignorance" could help Americans use reason constructively & arrive consensually at a notion of redistributive justice that would strengthen "Great Society" programs & social-democratize America, but evidently it didn't catch on.
The material & ideological power of capital is the strongest in the belly of the beast. Perhaps, being the most powerful empire & global guarantor of capitalism and being social democratic in European fashion are mutually exclusive (the UK, the global hegemon before the USA, is also the least social democratic among West European powers; in fact, some of the English don't want to be part of Europe). Besides, racism is not compatible with universal programs.
Americans lost a couple of chances to lay the groundwork for social democracy: black reconstruction after the civil war & mass mobilization during the Great Depression. In 1947 any hope for social democracy in America got buried. And now we are seeing the Endgame of social democracy in the Third Way (with Green scissors in Germany) in Europe.
Yoshie