Answer:
Americans knew what was happening, but some followed it closely, while other details were veiled as with any news report. During the late 1930s, it was well-known (and not entirely controversial) that the U.S. denied entry to some refugees from Hitler's regime, and in the 1940s, a precursor to the United Nations publicly condemned the Nazi policy of extermination. However, during that time, when genocide was a neologism, it would have been difficult for everyday Americans to fully comprehend what was happening.
