Einstein traveled widely in the 1920s, both as a spokesman for liberal causes and as an esteemed member of the physics community. He visited England, France, Austria, Czechoslovakia, and South America and traveled east as far as Japan, returning by way of Palestine and Spain. In 1922 he went to Sweden to accept a Nobel Prize in physics. Between 1930 and 1933 he spent each winter in Pasadena at the California Institute of Technology, each spring in Berlin, and each summer near Berlin in a home at Caputh.

Anti-Semitism was openly pursued by the powerful political right and the emerging Nazi party since 1919. Nazi physicists and their followers violently denounced Einstein's theory of relativity as "Jewish-Communist physics." At times his friends feared for his safety. Such anti-Semitism was one reason why Einstein, although he believed in world government rather than nationalism, gave public support to Zionism. "In so far as a particular community is attacked as such," he said, "it is bound to defend itself as such, so that its individual members may be able to maintain their material and spiritual interests... In present circumstances the rebuilding of Palestine is the only object that has a sufficiently strong appeal to stimulate the Jews to effective corporate action." But he objected to a law that required him to join the official Jewish religious community in Berlin. He said, "Much as I feel myself a Jew, I feel far removed from traditional religious forms."

As the Nazi movement grew stronger, Einstein helped to organize a non-partisan group, within the Jewish community, that advocated a united stand against fascism. Hitler's climb to power, bringing official support of vicious anti-Semitism, was making the position of Jews and other opponents of Nazism impossible. After Einstein left Germany in 1932 he never returned. In March 1933 he once again renounced German citizenship. His remaining property in Germany was confiscated, and his name appeared on the first Nazi list of people stripped of their citizenship.