In October of last year, Menachem Rosensaft wrote an article titled, "Israel's Jewish Essence Is Non-Negotiable: A Response to Mahmoud Abbas." In the article Rosensaft stresses that Israel must remain Jewish. This is a standard Zionist position. Zionism is defined as Jewish Nationalism.
This month (barely five months after the pro Jewish Nationalist article), Menachem Rosensaft wrote an article titled. "White Nationalism: A Scourge That Won't Go Away".