...Einstein's decision reflected a major transformation in his life. Until the completion of his general theory of relativity, he had dedicated himself almost totally to science. But the anti-Semitism that was oozing up around him in Berlin led him to reassert his identity as a Jew and to feel more committed to defending the culture and community of his people. "I am not keen on going to America, but am just doing it on behalf of the Zionists," he wrote to his French publisher. "I must serve as famed bigwig and decoy-bird ... I am doing whatever I can for my tribal brethren, who are being treated so vilely everywhere."...

...Thousands of spectators, along with the fife-and-drum corps of the Jewish Legion, were waiting in Battery Park when the mayor and other dignitaries brought Einstein ashore on a police tugboat. The crowd, waving blue-and-white flags, sang "The Star-Spangled Banner" and then the Zionist anthem, "Hatikvah." The Einsteins and the Weizmanns intended to head directly for the Hotel Commodore, in Midtown. Instead, their motorcade wound through the Jewish neighborhoods of the Lower East Side late into the evening. "Every car had its horn, and every horn was put in action," Weizmann recalled. "We reached the Commodore at about 11:30, tired, hungry, thirsty, and completely dazed."

One group was missing at most of the subsequent welcoming ceremonies and celebrations: the leaders of the Zionist Organization of America. Supreme Court Justice Louis D. Brandeis, who was its honorary president, did not even send pro forma official greetings or congratulations. Brandeis had traveled with Weizmann to Palestine in 1919, and the following year had gone to London to be with him at a Zionist convention. But shortly afterward they began to feud. Their fight partly stemmed from a few differences over policy; Brandeis wanted the Zionist organizations to focus on sending money to Jewish settlers in Palestine and not on agitating politically. It was also partly an old-fashioned power struggle; Brandeis wanted to install efficient managers and take power from Weizmann and his more ardent eastern European followers. But above all, it was a clash of personalities. Weizmann was born in Russia, emigrated to England, and shared Einstein's disdain for Jews who tried too hard to assimilate. Brandeis was born in Louisville, Kentucky, graduated from Harvard Law School, prospered as a prominent Boston lawyer, and was appointed by President Wilson to be the first Jewish justice on the Supreme Court. His crowd tended to look down on unrefined and unassimilated Jews from Russia and eastern Europe...

...two of Brandeis's closest associates expressed misgivings. His protégé Felix Frankfurter, then a professor at Harvard Law School, and Judge Julian Mack, the person Brandeis had tapped to be president of the Zionist Organization of America, argued that it would be better if Einstein's visit were cast primarily as a trip to lecture on physics, rather than one to raise money for Palestine...

The resistance to Einstein's mission came not only from the Brandeis camp of cautious and restrained American Zionists, but also from successful New York Reform Jews of German heritage, many of whom were opposed to Zionism. When Einstein invited 50 or so of New York's most prominent Jews to a private meeting in his hotel, many of them declined. Paul Warburg, who had served as his agent soliciting lecture fees, wrote:

My presence would be of no use; on the contrary, I fear that, if at all, its effect would be rather to cool things down. As I already told you on another occasion, I personally have the greatest doubts relating to the Zionist plans and anticipate their consequences with genuine consternation.

Other rejections came from Arthur Hays Sulzberger of The New York Times; the politically connected financier Bernard Baruch; the lawyer Irving Lehman; the first Jewish Cabinet secretary, Oscar Straus; the philanthropist Daniel Guggenheim; and the former Congressman Jefferson Levy.

On the other hand, Einstein and Weizmann were wildly embraced by less assimilated and more enthusiastic Jews, the ones who tended to live in Brooklyn or on the Lower East Side rather than on Park Avenue...