Agudat Yisrael
In 1947, Warhaftig immigrated to Mandatory Palestine. Initially he joined the Hapoel HaMizrachi party, a religious-zionist party, and in 1949 he was elected to the first Knesset as part of the United Religious Front, an alliance between Mizrachi, Hapoel HaMizrachi, Agudat Yisrael and Poalei Agudat Yisrael. In 1948-1963 he taught Jewish Law at the Hebrew University of Jerusalem.