A window has opened to the Orthodox community. We are being invited to help reshape the social dynamics of the American Jewish community. With courage and vision, we need to act on this opportunity by understanding the important changes that have occurred over the last decades and rethinking the way we engage the broader Jewish community. Never before in the history of US Judaism has there been openness to Orthodoxy as sincere and real as that which we see today. I am not referring to openness in terms of individual Jews embracing Orthodoxy. For many practical and philosophical reasons, such individuals will always be relatively few. Rather, I am referring to the openness of non-Orthodox and interdenominational institutions to learning from the experiences and insights of their Orthodox brethren. To wit, numerous hallmarks of Orthodox life have been adopted by other movements. Conservative and Reform Day schools are growing in number and size. We are seeing broad adoption of the more participatory and Hasidic worship style. Non-Orthodox women's groups have discovered mikve use as a form of spirituality, and the new hip name for adult education institutes outside of Orthodoxy is Kollel. This phenomenon presents the Orthodox community with an unprecedented chance to engage with and contribute to the wider community in far-reaching and significant ways. But it is one that we can seize only by moving beyond our traditional parameters regulating inter-denominational contacts, which have long since outlived their purpose and usefulness. Today, Orthodox rabbis have practically disappeared from interdenominational boards of rabbis. In some communities, the Orthodox Rabbinical Council actually forbids it members from joining interdenominational boards. Interdenominational study groups or even social action groups are practically unheard of. The vast majority of Orthodox synagogues would never consider having a joint Simhat Torah celebration, Shavuot night learning program, or a Tisha Be'av ceremony with a non-Orthodox congregation. HISTORICALLY, there is strong precedence for such reticence about interdenominational involvements. In 1954, even Rabbi Joseph B. Soloveitchik strongly discouraged Orthodox rabbis from pursuing matters of "spiritual religious interest" with non-Orthodox rabbis, while in 1956, an influential declaration signed by a dozen outstanding Orthodox luminaries, including Rabbi Moses Feinstein, prohibited membership in interdenominational groups. But it is at the peril of American Judaism, that we ignore the vital and fundamental differences between the 1950s and today. The concern that drove the rulings of 50 years ago is no longer relevant. The 1950s and 60s were years of enormous struggle for American Orthodoxy as children of Orthodox parents continued to leave Orthodox life in great numbers and the culture militated hard against Orthodox Jews retaining their traditional observance. The attraction of Conservative and Reform Judaism was very great in these circumstances. What Rabbi Soloveitchik called an ideological battle, with the future of Orthodoxy at stake, was being waged against non-Orthodox movements. In this context, we can readily understand how any activity or association that implied Orthodoxy's recognition of Conservative or Reform rabbis as peers would have signaled to the Orthodox community that all denominational options were equally acceptable. In Soloveitchik's words, "Too much harmony and peace can cause confusion of the minds, and will erase outwardly the boundaries between Orthodoxy and other movements." Today, however, the Orthodox community has become a stable, indeed growing, presence successfully retaining its youth. The ideological battle is, for all intents and purposes, over. Additionally, even as denominational lines continue to exist within the Jewish community, the only line that is thick and red divides those who ignore rising Jewish apathy and those ready to combat it. In the 1950s and indeed into the 1970s, intermarriage was statistically negligible. Today, standing as it does at nearly 50%, intermarriage is the greatest threat to the entire Jewish community. Indifference towards one's Jewish identity, the frequent precursor of intermarriage, is widespread among America's Jews, as is evidenced by the paltry rates of synagogue affiliation that turn up in study after study. Anyone willing to fight for Jewish survival is a de facto ally. Several years ago, I joined with non-Orthodox colleagues in creating a retreat program for our synagogue's teenagers. One retreat was dedicated to the theme of inter-dating and intermarriage. The discussions were passionate and serious, and the openness to sharing and listening was breathtaking. The Orthodox teens made a palpable impact on their peers, and all it took was the courage to engage. The window is open, and it may represent our last, best chance to effectively counter the trends that have been eroding both the quality and quantity of Jewish religious life in the US. The only question facing us is whether we help each other by sharing resources, ideas, and comradeship, or hobble through by withholding spiritual capital in the name of an ideological battle that effectively ended a generation ago. The writer is the rabbi of the B'nai David-Judea Congregation (LA) and the president of the Southern California Board of Rabbis.