There was a very serious communist strain among American intellectuals before the war. America was a more tolerant place in those days, and Communists were not treated as pariahs. That ended with the McCarthy era.
“Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passions, they cannot alter the state of facts and evidence.”
“I think that for the highest achievements nowadays... need to have the stable as a rock scientific base. And also need to own modesty.”