 Cohen’s conception of the essentially ethical nature of Judaism had important consequences for his view of Judaism’s relation to other religions, as well as his views of Zionism and the Jews’ place in Wilhelmine Germany. Because Cohen thought the ethical nature of Judaism was expressed by its monotheism, he believed that at least some forms of Christianity had the same ethical nature. While for Cohen Judaism was the original religion of reason, liberal Protestantism expresses universal ethical ideals and is a religion of reason as well. (He thought Catholicism failed to express properly universal ideals. He seems not to have considered Islam.) At the same time, because for Cohen Judaism ultimately aims at an ethical ideal that includes all humanity, he rejected the nationalism he saw in non-liberal forms of Judaism and was a vocal critic of Zionism. In a public exchange with Martin Buber, Cohen argued that Jews had an obligation to remain in their countries of birth, so that their religious communities could serve as exemplars for the rest of humanity of communities unified by ethical laws. He died in 1918, before the increasing virulence of antisemitism in Germany could make him reconsider this argument.