During the Middle Ages, Jews were members of a semi-independent polity within a larger polity.
Jewish status is defined by the divine election of Israel and his descendants. One does not become a Jew by one's own volition.
It was in the early 1960s that my late revered teacher, Professor Abraham Joshua Heschel, became the first major Jewish theologian in America to enter into dialogue with Christian theologians on a high theological level.
All the questions discussed in the Talmud and related rabbinic literature are normative questions: either they are questions of what one is to think or what one is to do. Every prescribed thought has some practical implication; every prescribed act has some theoretical implication.
Perhaps the main stumbling block to a better, and more fruitful, theological relationship with Judaism and the Jewish people has been the tendency of many Christian theologians to see the Christ event as the end of history.
I first came to Jewish-Catholic relations in 1963, while studying for the rabbinate at the Jewish Theological Seminary in New York.