In the first part of this essay, I seek to briefly elucidate how Moishe Postone distinguishes modern antisemitism from other forms of racism. Following that, I aim to demonstrate how, in spite of its specificity, the former is able to work in tandem with the latter.
All forms of antisemitism attribute an enormous degree of power to the Jews. For instance, ‘the power to kill God, unleash the Bubonic Plague and, more recently, introduce capitalism and socialism.’  In modern antisemitism, which arose in late nineteenth-century Europe, the power ascribed to the Jews can be distinguished not only quantitatively but also qualitatively. Whereas most racisms ascribe ‘a concrete physical or sexual power’ to the Other,  in the modern antisemitic worldview, the kind of power attributed to the Jews is ‘mysteriously intangible, abstract and universal.’  This power ‘does not manifest itself directly, but seeks a concrete carrier—whether political, social, or cultural—through which it can work.’  Insofar as ‘[it] is not limited concretely… [it appears] extremely difficult to check.’  This power is also only discernible via its destructive effects. Thus, ‘it is hidden—conspiratorial.’  In nuce,the Jews are seen to constitute ‘an immensely powerful, intangible, international conspiracy.’ 
Modern antisemitism then, considers the Jews not as an inferior race, but rather as ‘anantirace opposed to humanity.’  That is, International Jewry is regarded as an evil power from which humanity must be liberated or redeemed,  rather than as a collection of primitives who need to be subordinated. While other races are seen to pose a passive threat—‘the power of the oppressed (as repressed)’  —which must be checked, ‘violently if necessary’, the Jews represent an ‘active and lethal threat’  that must be vanquished or eliminated. Hence why the Nazis’ extermination of Jewry was both total and autotelic, i.e., an end-in-itself.  By contrast, they only killed Slavs and Poles liable to generate resistance, ‘so that the rest could be exploited as a class of helots’. 
Although I cannot elaborate fully here, Postone accounts for the distinctiveness of modern antisemitism thus. He argues that it served as a framework for comprehending the complex dynamism of the modern capitalist world. It held the Jews responsible for economic crises and identified them with the various forms of social restructuration and dislocation caused by rapid industrialisation: ‘explosive urbanisation, the decline of traditional social classes and strata, and the emergence of a new strata of bankers, capitalists, and professionals along with a large, increasingly organised industrial proletariat.’  Which is to say, the abstract domination of capital—’which subjects people to the compulsion of historical forces they cannot grasp directly’—became reified or fetishized as the domination of International Jewry.  Thus, modern antisemitism is a foreshortened form of anti-capitalism or, alternatively, ‘the socialism of fools’ (Bebel).
Though modern antisemitism is distinct from other racisms, they can still harmonise—‘different’ does not mean ‘opposed’. America is rapidly diversifying. In 1980 whites constituted almost 80% of the US population, while Latinos made up 6.5% and Asian-Americans 1.8%. By 2019, the proportion of whites had dropped to 60.1%, while Latinos and Asian-Americans made up 18.5% and nearly 6%, respectively.  The American alt-right, who adhere to an ethnic brand of nationalism, have evaluated these demographic shifts in racist terms: they believe native whites are being replaced by non-white aliens. Behind this displacement process, though, lies the hidden hand of the Jews supposedly. Non-white migrants are regarded as the Jews’ pawns, used by them to undermine the white population. Three terrorist attacks in the US have resulted from this conspiratorial vision: in October 2018, 11 persons were murdered at a synagogue in Pittsburgh, Pennsylvania; in April 2019, one person was killed at a synagogue in Poway, California; in August 2019, 23 persons were murdered at a Walmart in El Paso, Texas in an anti-Latino attack.  Meanwhile, in Europe, right-wing populists, such as Hungary’s prime minister Viktor Orbán and Italy’s former deputy prime minister Matteo Salvini, have accused the Jewish investor and philanthropist George Soros of attempting to swamp their countries with refugees.
Modern antisemitism and anti-black racism are also able to combine. Just as the Jews were seen as standing behind the rise of mass labour movements in the late nineteenth and early twentieth century, so George Lincoln Rockwell, founder of the American Nazi Party, claimed that ‘Jewish Communists’ masterminded the civil-rights movement. Rockwell considered racial mixing between whites and blacks to be part of a Jewish plot to weaken the whites and thereby better control them. He traced this conspiracy back to the German Jewish émigré Franz Boas, whose anthropological work largely centred around deconstructing pseudo-scientific racial hierarchies. 
Postone argues that modern antisemitism holds the Jews responsible for the abstract form of domination exerted by capital. This is why, unlike other forms of racism, it possesses an apparently emancipatory dimension. Despite their distinction, though, modern antisemitism and other racisms can still operate together, as demonstrated above.
 Postone, ‘Anti-Semitism and National Socialism’, 106.
 Postone, ‘The Dualisms of Capitalist Modernity’, 47.
 Postone, ‘Anti-Semitism and National Socialism’, 106.
 Postone, ‘The Holocaust and the Trajectory of the Twentieth Century’, 89.
 Postone, ‘Anti-Semitism and National Socialism’, 105. ‘No functionalist explanation of the Holocaust…can even begin to explain why, in the last years of the war, when the German armies were being rolled over by the Red Army, a significant proportion of vehicles was used to transport Jews to the gas chambers, rather than for logistical support’ (Ibid.).
 Postone, ‘The Holocaust and the Trajectory of the Twentieth Century’, 89. According to Eric Hobsbawm, the middle and lower-middle classes, those ‘little men in a society that crushed them between the rock of big business on one side and the hard place of rising mass labour movements on the other’, formed the backbone of ‘non-traditional movements of the radical Right [which] emerged in several European countries in the late nineteenth century in reaction against both liberalism… and the rising socialist working-class movements’ [Hobsbawm, The Age of Extremes,119.]. For them, ‘[Jews] could serve as symbols of the hated capitalist/financier; of the revolutionary agitator; of the corroding influence of ‘rootless intellectuals’ and the new mass media’ (Ibid.).
 Frey, ‘The nation is diversifying even faster than predicted, according to new census data’.
 As an aside: The disconcerting frequency of far-right attacks signifies the decline of what Hegel termed Sittlichkeit—or more pointedly, a descent into barbarism. In 1993 in a German city called Solingen ‘[a group of] neo-Nazi teenage skinheads [burned] down a house inhabited by immigrants, killing six members of a Turkish family.’ Commenting on the incident, Hobsbawm noted: ‘In the years before Hitler came to power in Germany and Austria, acute though racial tensions and hatreds were, it is difficult to imagine that they would have taken [this] form… yet in 1993 such an incident shocks but no longer surprises when it occurs in the heart of tranquil Germany’ [Hobsbawm, The Age of Extremes,460.].
Baker, Lee D., ‘The Cult of Franz Boas and his “Conspiracy” to Destroy the White Race’, in Proceedings of the American Philosophical Society, Vol. 154, No. 1 (March 2010), pp. 8-18.
Frey, William H., ‘The nation is diversifying even faster than predicted, according to new census data’, Brookings, July 1, 2020, accessed May 10, 2022.
Hobsbawm, Eric, The Age of Extremes, London: Abacus, 1995.
Postone, Moishe, ‘Anti-Semitism and National Socialism: Notes on the German Reaction to “Holocaust”’, in New German Critique,No. 19, Special Issue 1: Germans and Jews (Winter, 1980), pp. 97-115.
Postone, Moishe, ‘The Dualisms of Capitalist Modernity: Reflections on History, the Holocaust and Antisemitism’, in Jews and Leftist Politics, ed. Jack Jacobs (Cambridge: Cambridge University Press, 2017), pp. 43-66.
Postone, Moishe, ‘The Holocaust and the Trajectory of the Twentieth Century’, in Catastrophe and Meaning: The Holocaust and the Twentieth Century, ed. Moishe Postone and Eric Santner (Chicago: University of Chicago Press, 2003), pp. 81-116.