The issue of Chuck Hagel continues to dominate the conversation in the organized Jewish community, where prominent individuals and organizations contend with each other to shape the narrative and influence Barack Obama’s thinking on the nomination.

But it’s about more than Hagel and his potential nomination. The dispute is an example of the growing fragmentation in the U.S. Jewish community over advocacy on Israel.

On Wednesday, James Besser—longtime Washington reporter for The Jewish Week—wrote a biting op-ed in the New York Times, in which he castigated mainstream organizations like AIPAC, the ADL, and the AJC for giving in to extremist groups (“zealots”) who insert their “fringe-driven politics” into the community’s discourse. He compared these groups to the NRA in the aftermath of the Sandy Hook murders. The AJC’s David Harris responded just as sharply, writing that Besser’s claims were “replete with glaring errors of omission and commission” and “absolute and total rubbish.”That Harris’s response was to argue the AJC is “centrist and non-ideological” is telling, as it hints at the deeper struggle within the community and among its representative institutions.I spoke with Besser to further clarify his concerns. He worries that the rightward drift in the U.S. Jewish community endangers both the pro-Israel movement in the U.S. (because it’s becoming alienated from the majority of U.S. Jews) and Israel itself (because it encourages its leaders “to believe they can ignore U.S. policy, because U.S. Jews have its back”).

Besser notes that the Times left out an important point in his piece. Because the big centrist groups (like AIPAC, the ADL, the AJC) are facing challenges from more rightist groups and individuals (like the Emergency Committee for Israel and its supporters), they face a critical dilemma. Part of their function is to strengthen the U.S. relationship with Israel, which necessarily translates into supporting the government of Israel. Because the current government is often in conflict with the U.S., these organizations have trouble balancing out their support for Israel with even friendly criticism when they think Israeli policy is harming both Israel and America.

Peter Beinart’s research has also supported such arguments. Still, some argue that these aren’t new trends, or that they aren’t as stark as Beinart, Besser, and others make them out to be. Other observers dispute the intensity of changes, and whether other factors—such as economic conditions, or shifts within the centrist groups themselves—are more relevant.

Either way, it is clear that the nature of advocacy on Israel is changing.

In the beginning, there were real divisions in the Jewish community over U.S. policy toward the founding of Israel. After 1948, the Jewish community’s official politics and interaction with the government was driven by quiet consensus. There was never complete agreement, and sometimes intra-communal disputes got really vicious. Declining anti-Semitism, increasing integration into the broader American community, Israel’s victory in the 1967 War, and a strengthening U.S.-Israel relationship in the 1970s prompted a more comfortable and assertive institutional presence in politics.

Today the American-Israeli relationship is not in any real danger of suddenly being undermined. The two countries are tied together by multiple bonds, including broad public support, the momentum of the Cold War, shared strategic interests (intelligence, weapons development), and so on. In addition, the popularity of Israel among the American public makes it less likely that elected officials will start a fight over the issue, since the benefits are uncertain but the drawbacks clear.

But the trends within the community are well-defined. Gary Rosenblatt, another keen observer, writes, “As Jews move in two opposite directions, away from and towards engagement [with Israel], we are becoming an increasingly complicated and diverse people with fluid definitions, from what it means to be ‘pro-Israel’ to ‘who is a Jew?’”

As Besser continues, mainstream U.S. Jewish groups are facing pressure from both the right-wing government in Israel (which may become even more rightist after the January election) and the right-wing groups and individuals in the U.S., who run on a single issue and are less concerned with developing ties and ideas across the political spectrum. Left-wing groups like J Street are also beginning to pose a challenge—though, because most leftist Jewish groups are either anti- or non-Zionist, the centrist organizations can more easily fend them off or ignore them.

The big groups do react differently. Contrast the AJC’s response to Besser’s piece with the Jewish Council for Public Affairs’ “no comment.” But they are all being squeezed from multiple sides. And developments in the Middle East are likely to make these internal disputes sharper and more consequential: how to respond to the Iranian nuclear program, Palestine’s international campaign for legitimacy, West Bank settlements, the growing strength of rightist parties in Israel.

The rhetoric over the Hagel nomination has often been hyperbolic, and so it seems fitting to note that as the struggle over how to define “pro-Israel” continues into 2013, nothing less than the very identity of the American Jewish community is at stake.