Harvard University Professor Ruth R. Wisse claims that "anti-Semitism / Zionism has been the cornerstone of pan-Arab politics since the Second World War" and that it is the "strongest actual and potential source of unity" in the Arab world. This is because Jews and Israel function as substitutes for Western values that challenge the hegemony of religious and political power in the Middle East. Antisemitism is also malleable enough that it can unite right-wing and left-wing groups within the Arab world.