The debate between contemporary cosmopolitans and advocates of nationalism is hardly new. Nevertheless, much of it is based on the erroneous assumption that cosmopolitanism should be seen as an outgrowth of liberalism, and that both should be considered as the complete conceptual opposites of nationalism. In this article I focus on two of the post-war Jewish anglophile intellectuals who took part in this debate during the Cold War years: the Oxonian liberal philosopher Sir Isaiah Berlin (1909-97) and the Israeli historian Jacob L. Talmon . I use their examples to argue that the dividing line between cosmopolitans and advocates of nationalism should not be regarded as signifying the distinction between liberals and anti-liberals; in fact, this debate also took place within the camp of the liberal thinkers themselves. I divide my discussion into three parts. Firstly, I examine Berlin's and Talmon's positions within the post-war anti-totalitarian discourse, which came to be known as 'liberalism of fear'. Secondly, I show how a sense of Jewish identity, combined with deep Zionist convictions, induced both thinkers to divorce antinationalist cosmopolitanism -which they regarded as a hollow, illusionary ideal associated with impossible assimilationist yearnings -from the liberal idea. I conclude by suggesting that, although neither man had ever developed a systematic theoretical framework to deal with the complex interactions between ethno-nationalism, liberal individualism and multiculturalism, Berlin's vision of pluralism provides the foundations for building such a theory, in which liberalism and nationalism become complementary rather than conflicting notions.