Rarely has an issue exposed the deep rift that exists – and has existed for some time now – between two distinct tribes of the Jewish people. That is precisely what the Iran nuclear deal is doing to Jews in America.On one side are the US Jews of liberal persuasion who overwhelming belong to non-Orthodox streams of Judaism or are unaffiliated. These are Jews who consistently vote for Democratic politicians and identify with the more liberal wing of American society.On the other side are the American Jews who are more conservative in their political outlook. Many belong to the relatively small but fast-growing Orthodox communities – particularly in the New York area – or in the more conservative wing of Conservative Judaism. They tend to vote Republican.Many issues divide these two Jewish tribes, from abortion and same-sex marriage to the role of religion in public life and economic policy. The two tribes also differ on their lifestyle choices.Liberal Jews tend to view full integration into American society as an important value. Clannishness, parochialism and self-segregation are eschewed for full cooperation and coexistence. Liberal Jewish parents tend to send their children to the same schools as other Americans and live in the same neighborhoods. They prioritize normalization and integration over Jewish identity and continuity.In contrast, the more conservative tribe is willing to pay a societal price for maintaining a self-imposed exile from the broader American society. Parents send their children to Jewish day schools, yeshivot or seminaries.Neighborhoods are chosen for walking-distance proximity to a synagogue and therefore tend to have large Jewish populations. The two groups also differ on their positions vis-à-vis Israel. Identification with Israel and the policies of the recent governments of Prime Minister Benjamin Netanyahu tends to be high among members of the conservative tribe. Liberal tribe members, meanwhile, though pro-Zionist tend to be more critical on issues such as settlement policy, the Orthodox monopoly over religious services, legislation calling for Israel to emphasize its Jewish over its democratic character, and military action against Palestinians.The latest symptom of this rift is a letter, signed by 340 rabbis, most of whom belong to liberal streams of Judaism, supporting US President Barack Obama and his nuclear deal with Iran.It is the latest salvo in a battle between the two Jewish tribes of America. This battle has been particularly bitter with neither sides pulling punches.The New York Times presented a position with which many liberal US Jews identify, editorializing earlier this month that “the unseemly spectacle of lawmakers siding with a foreign leader against their own commander in chief has widened an already dangerous breach between two old allies,” as if members of the US Congress should be suspected of dual loyalty simply for disagreeing with their president.Conversely, there have been instances where outlandish charges of anti-Semitism or “self-hating Jew” have been leveled at those who support the nuclear agreement.That opposition to the Iran deal inside Israel is nearly a consensus opinion held by members of both the Left and the Right has compounded the rift within American Jewry.Issues such as settlements, the Orthodox rabbinic monopoly and balancing Israel’s Jewishness and democracy are fiercely debated inside Israel.The liberal tribe in America could find its ideological partner in Israel. But the strong support for the Iran agreement expressed by a large segment of liberal US Jewry does not resonate equally in Israel. This state of affairs reveals the deep rift that exists today between US liberal Jews on one side and their more conservative American brothers and sisters and Israelis on the other.But it is important to remember that we are all one people.The Iran deal is a single issue that as important as it might be for all sides does not justify jeopardizing Jewish unity. Political disputes will come and go, but we must not allow dissent over this or that policy decision to tear us apart. We may be members of different tribes. But we belong to a single people.