Why interfaith marriage should be part of URJ congregational practices:

• The goal is Jewish continuity. The critical question is how best to
  serve that goal. Numbers increase by addition, not subtraction.

• The first imperative is to not foreclose future relationships between
  the couple and the Jewish community. Refusing participation in the
  wedding may be treated with lifetime resentment by the Jewish partner,
  even if the marriage doesn't endure.

• Jewish status, especially of the children, is a major concern. There
  are two kinds of Jewish status:

• Jewish identity, for which there are four pillars: lineality
  (either parent) or conversion, Jewish self-identification, Torah
  (meaning all of Jewish learning and tradition) as the primary source of
  guidance, and the mitzvah system (life cycle and behavior). At least
  three pillars are needed.

• Status as a ger toshav (literally, a resident stranger, also settled
  sojourner or "Friend of the Folk"). The non-Jewish partner who
  participates in Jewish community activities -- and especially who raises
  Jewish children -- has this status, and is thereby included with the
  "mixed multitude" that stood at Sinai.

• The rabbi must be engaged in the process and should spend extended
  time (Rabbi Brenner allocates 9 hours) with the couple, explaining Judaism
  and the importance of Jewish continuity, and encouraging the couple to
  decide how to raise any children that may be born from the union. We must
  discourage choices of "neither" and "both." And we must not foresake a
  couple that decides to be "non-Jewish."

• Rabbi Brenner, who has many years of experience counseling interfaith
  couples, has concluded that a process called "convergence" happens first
  ("Yes, I can raise a Jewish child"). Conversion sometimes comes years
  later.

• The tone of the marriage is set during the wedding arrangements.
  Halachically, the wedding is conducted by the clergy who supervises the
  ketubah signing and exchange of rings. The blessings and speeches,
  whether by clergy or family, are secondary. Be there, if only for the
  Jewish relatives. Openness regarding participation will be remembered and
  appreciated by the couple and the Jewish partner's family.

• It is misguided, short-sighted, and transparently contradictory to
  recruit interfaith married couples but reject the process of marrying
  them.

We increase numbers and strengthen the Jewish community by adding
children, gerei toshav, converts, and returnees (whose families
separated from Judaism and who rediscover their roots). And the
non-Jewish partners we tend to get are the best, the real keepers.

For more details, see http://www.reevebrenner.com/books/chewish