Reform Jews’ opposition to Zionism as summarized by Dan Cohn-Sherbok and Lavinia Cohn-Sherbok (2010): Opposition to Zionism came from the two extreme wings of the religious spectrum [Reform and Orthodox]. On the one hand, the nineteenth-century Reformers saw assimilation, not the creation of a Jewish homeland, as the solution to anti-Semitism. Reform Jews had consistently stressed the universal message of Judaism [obey God’s ethical laws and He will look after you]. They understood the Jewish heritage as a call to ethical monotheism. In the words of the biblical prophet Micah, the Jew was to do justice, to love mercy and to walk humbly with thy God (6:8). The mission of Judaism was to bring the knowledge of the One God and His ethical will to the nations of the world. They were uneasy with the particularistic elements of the tradition and they had already abandoned prayers for the restoration of the sacrificial system in the Temple in Jerusalem.
After Herzl issued his summons to the First Zionist Congress [1897, Basel, Switzerland], the Progressive German rabbis made a statement declaring that the Jewish faith obligated all Jews to serve the countries in which they live. The American Reformers were even more downright. Isaac Mayer Wise (1819-1900) , the first president of the American Reform rabbinical college declared: “We denounce the whole question of the Jewish State as foreign to the spirit of the modern Jew of this land, who looks upon America as his Palestine and whose interests are centred here.” These early Reformers believed that the salvation of the Jews lay not in the return to the Promised Land, but in the emergence of a liberal, educated and pluralistic society”
Many members of the American Reform Movement persisted in their opposition to Zionism right up until World War II. As late as 1942, a number of American anti-Zionists gathered together to formulate a program of action. This body asserted that the political aspirations of the Zionists were contrary to the universalistic spirit of Judaism and that Zionism threatened Jewry in that it called into question the loyalty of the Jews to the countries in which they lived. Even after World War II, the American reform liturgy for the Passover meal ended not with “Next Year in Jerusalem”, but with “God Bless America!”
Reform Jews therefore objected to Zionism because it undermined Jewish allegiance to host nations and because it emphasized the ethnic, nationalistic spirit of Judaism (Dan Cohn-Sherbok and Lavinia Cohn-Sherbok, “Judaism: A Beginner’s Guide”, Oneworld, 2010).