Isaac M. Wise was the founder of American Reform Judaism, a liberalising, modernising movement that sought to bring Judaism in line with the American ideals of universal freedom and progressive democracy. A builder rather than a theologian, he united the many disparate congregations that had been transplanted to America from Central Europe in the mid nineteenth century. By 1881 not more than a dozen congregations out of 200 were unaffiliated with Reform and Wise, as he entered old age, felt content at a job well done. But it was now that Reform faced its biggest challenges to date. Widespread apathy from within Reform saw the movement stagnate, but for Wise there was a much more visible threat: political Zionism. But why did Wise attack Zionism so vociferously when it had fewer than 15,000 active American supporters on the eve of his death? Why did it preoccupy his writings when the wider community – both Jew and Gentile – hardly noticed the Zionist movement in his lifetime? At the heart of this was a conflict over what it meant to be a Jew post-emancipation, a conflict which is still very much raging.