Ron Paul, one of the candidates vying for the Republican Party's presidential nomination, has met a representative from the extremist anti-Zionist group, Neturei Karta.
Mr Paul, who has drawn criticism for a catalogue of controversial remarks about Israel and the Holocaust - as well as on race and homosexuality - shook hands with Rabbi Yisroel Dovid Weiss at an event in New Hampshire.
The Monsey rabbi, whose grandparents died in Auschwitz, previously met Iranian leader Mahmoud Ahmadinejad at a conference questioning the Holocaust.
During the conversation, Rabbi Weiss said that Judaism was a religion and "should never be transformed into a nationalism".
Mr Paul, who is staunchly against the US giving aid to Israel, responded by saying that the suggestion was "good advice".