Although most of the rabbis in the Talmud considered the Deuteronomic law to refer only to marriage to Canaanites, they considered all religious intermarriage to be prohibited at least rabbinically.
Gradually, however, many countries removed these restrictions, and marriage between Jews and Christians (and Muslims) began to occur.
First and foremost, Hayes holds that the fear of profaning the seed of Israel was the underlying rationale for the ban in exogamous marriage, rather than the ritual impurity of Gentiles in general.
She also argues that the regulations on intermarriage in the times of Ezra were different from the restrictions on intermarriage according to the book of Deuteronomy.
(Moabites were descendants of Lot, Abraham's nephew, not Canaanite.) In several places in the Tanakh, there are relations which obviously were intermarriages - for examples, King David is described as marrying the daughter of the king of Geshur, In any case, after the Babylonian Captivity disquiet seems to have arisen about such exogamy; the Book of Malachi declares that the intermarriage with "the daughter of a foreign god"(something different from marrying a non-Jewish person) that had occurred was a profanity, though Malachi also argues against divorce.
Christine Hayes compares the Deuteronomic and Ezran viewpoints on intermarriage, and discusses in terms of ritual impurity and the fear of profaning the seed of Israel.
For example, the Ezra ban on intermarriage was different in that it was 1) Universal in scope, and 2) had the rationale that intermarriage was the profanation of the holy seed of Israel.
She elaborates on these differences by saying that the prohibition at the time the Torah was written was not based on the ritual impurity of all Gentiles; rather, only the Gentiles of the seven Canaanite nations that were specified were to be avoided.
Progressive rabbinical associations have no firm prohibition against intermarriage; according to a survey of rabbis, conducted in 1985, more than 87% of Reconstructionist rabbis were willing to officiate at interfaith marriages, The Central Conference of American Rabbis, the Reform rabbinical association in North America and the largest Progressive rabbinical association, consistently opposed intermarriage at least until the 1980s, including their members officiating at them, through resolutions and responsa.
Today, however, Reform and Reconstructionist rabbis, according to Jack Wertheimer, seem not at all concerned about intermarriage and have nothing to say in public about it.
If our children end up marrying non-Jews, we should not reject them.