In 1933, the members of the Frankfurt School were targeted by the Nazi party as being "left-wing radicals" (in addition to being Jewish) and were exiled. They reconvened, somewhat later, at Columbia University in New York, with which they remained from July 1934 until early 1943. Their financial needs were met by an endowment from Felix Weil (their ostensive founder), so they were able to remain relatively independent and free to carry out their work.
After the war, only Horkheimer and Adorno returned to Frankfurt, the others preferring to remain in America. The tone of their works became, if anything, more melancholy and distressed as they realized that the the culture of German-Jewish intellectuals from which they had emerged was now hopelessly lost. Nevertheless, they both assumed academic posts at Frankfurt and carried on their theoretical work, which, especially for Adorno, was far more oriented towards memory and meditation on the past than toward a diagnosis of the present. This is evidenced in the subtitle of one of Adorno's last books: Minima Moralia: Reflections From a Damaged Life. In it, he lamented the culture destroyed by fascism while attempting to exorcise his guilt at having survived the war. All this he managed to sum up beautifully in one sentence: "To write poetry after Auschwitz is barbaric."