 He has written on Chabad messianism in opposition to the claim by some Chabad Hasidim that the last Lubavitcher Rebbe, Menachem Mendel Schneerson, may have been the long-awaited Jewish Messiah (i.e.the "Moshiach").He has received both criticism and praise for his self-published book "Can The Rebbe Be Moshiach?"