With the Party's permission he gave lectures on various Jewish matters during his stay in America. At that time the Jewish radical intelligentsia in America was under the influence of naive socialist cosmopolitanism, which expressed itself in scorn for Jewish national problems, and for the Yiddish language and culture. When Zhitlowsky in a series of lectures pointed out that there was no contradiction between progressive nationalism and the socialist ideal, he encountered strong opposition. Very soon, however, many of his erstwhile opponents turned into his most ardent partisans.