"Antisemitism is the socialism of fools" (German: "Der Antisemitismus ist der Sozialismus der dummen Kerle") is a quote that distills the fact that antisemitism is a misdirection of class warfare towards the wrong enemy; instead of targeting the bourgeoisie, the class conflict is instead re-directed at Jewish people.
According to British historian Richard Evans, it was probably coined by Austrian left-liberal politician Ferdinand Kronawetter, but is commonly attributed to the German social democrat August Bebel and sometimes to Karl Marx. The phrase was in wide circulation among German social democrats by the 1890s.