The nomination of Rabbi Richard Jacobs to head the Union for Reform Judaism is the latest coup for J Street. Less than three years after its founding, a member of J Street's rabbinic cabinet is being appointed to head the largest branch of American Judaism.

With the nominee to head the Reform movement supporting the goals and visions of J Street, it will be impossible for mainstream American Jewry to continue to marginalize J Street and its profoundly anti-Israel positions.

In choosing Rabbi Jacobs, the Union for Reform Judaism was strangely silent about his activities vis-a-vis Israel. It was as if Israel did not matter. The URJ announcement focused on Rabbi Jacobs' creativity, on his skills as a congregational rabbi and on his leadership in calling for changes in the administration of the URJ itself.

Even Rabbi Jacobs omitted from his resume that he is a member of the rabbinic cabinet of J Street and that he signed a J Street letter for the 2010 High Holy Days that concluded, "we encourage others to join us in backing J Street and its efforts to achieve peace and security for the state of Israel and her neighbors."

J Street's efforts include opposing stronger sanctions against Iran and opposing the U.S. veto of a recent U.N. Security Council resolution condemning Israel's settlements policy, to name just two of its efforts to disparage and delegitimize Israel.

To show just how far Rabbi Jacobs' appointment moves Reform Judaism from its traditional support of Israel, Rabbi Eric Yoffie, the current president of the URJ and its president for the past 16 years, called J Street's position on the Gaza offensive "morally deficient, profoundly out of touch with Jewish sentiment and also appallingly naive."

Rabbi Jacobs aggressively embraces J Street's push for a two-state solution to the Arab-Israeli conflict. His ideas on this are expressed in his hostility toward the "settlers," the people who in a different age were called chalutzim, or pioneers.

Last summer Jacobs took part in one of the weekly Friday demonstrations in Jerusalem orchestrated by the Sheikh Jarrah Solidarity Movement, a group that describes its own actions as victories against the "cowardly Zionists' perpetrating an 'apartheid state' and ethnic cleansing in Jerusalem."

Rabbi Jacobs, of course, does not subscribe to their hateful venom. So why did he participate in the demonstration?

He told the New York Jewish Week, "I take issue with residents of east Jerusalem [being] taken out of their homes to make room for Jewish settlers."

Rabbi Jacobs said he disagreed with 99 percent of what the Sheikh Jarrah movement stood for, but he was willing to stand there with demonstrators screaming at a Jewish family preparing for the Sabbath.

Was Rabbi Jacobs aware that the Israeli Supreme Court had issued an eviction notice for these "residents of east Jerusalem" because they refused to pay rent to their Sephardic Jewish landlord who has owned the property since the 1920s? What was the 1 percent with which he agreed that was so important that it overrode his judgment on the other 99 percent?

Rabbi Jacobs says he does not support the global Boycott, Divestment and Sanctions (BDS) campaign against Israel, but thinks that selective BDS campaigns against the settlements are different.

Again, his thinking is a profound change from the current Reform movement's position articulated by Rabbi Yoffie, who in criticizing the boycott of Ariel, which is over the Green Line, said, "But please, no boycotts. Israel's enemies don't need any help."

ARZA, the Zionist arm of the Reform movement, has started a campaign to educate Reform Jews about the BDS movement's attempt to delegitimize and brand Israel an apartheid state. Will Rabbi Jacobs be able to support ARZA's program, or will he portray the Jewish state as divided between good Jews and bad Jews, with the latter depicted as obstacles to peace and, therefore, as appropriate targets for castigation and exclusion.

Last Yom Kippur, Rabbi Jacobs presented a sermon titled "Standing together for Israel" in which he called J Street "pro-Israel, pro-peace" and quoted approvingly Peter Beinart's critique that young people don't support Israel because it is becoming theocratic and anti-democratic, and does not see Arabs as human beings.

Should a man who believes these things really be given the responsibility to lead a major branch of American Jewry? Is this just another example of the elite Jewish leadership being profoundly out of touch with the feelings of its mainstream constituency?

The Reform movement has always leaned toward the political left, but Rabbi Jacobs' appointment has the potential to drive Zionist Jews out of the movement and to create a schism with mainstream Jewry, much as J Street has set itself in opposition to the American Israel Public Affairs Committee, the Jewish organization long recognized in the U.S. Jewish community as representing its pro-Israel views to the Congress.

Has Reform Judaism reverted to the anti-Zionist stance it held in the first half of the 20th century, or has J Street staged a coup? In either case, where are the rank-and-file members who understand Israel’s fight for survival and its extraordinary efforts to achieve peace to speak out against such a disastrous course?

(Carol Greenwald, a Washington-area activist, is the chairman of Jews Against Divisive Leadership.)