In an October 2013 decision, the Israeli Supreme Court denied the request to recognize "Israeli" as a nationality, and gave several essential reasons for supporting a specific "Jewish" nationality over a general "Israeli" nationality.

First, since it is reasonable to assume that a person cannot have two nationalities, this change would compel Jewish citizens of Israel to choose between being "Israeli" and "Jewish." Most Israeli Jews would be forced into an impossible predicament: we see ourselves as both Jewish and Israeli, and one does not exclude the other.

Second, if the nationality of Jewish citizens of Israel were to be classified as "Israeli," the implication would be that Judaism is not a nationality for them but is solely a religion. This idea is antithetical to the fundamental doctrine of Zionism and its main thinkers, from Herzl to Ben-Gurion, who saw Zionism as the national movement of the Jewish people.

Third, if the nationality of Jewish Israelis is defined as "Israeli" rather than "Jewish," then the "national" bond we believe binds together Jews in Israel and Jews in the Diaspora will be severed.

The Court dealt with this last point extensively. It adopted the position that one of Israel's essential characteristics as a "Jewish state" is its responsibility for the fate of the entire Jewish people—including the Jews of the Diaspora. For example, the Israeli penal code applies to crimes that are committed against Jews "because they are Jews" even if those crimes are committed outside of Israel, and applies to property of Jewish institutions that is vandalized because it is Jewish as well. The State of Israel has thus taken upon itself the duty of protecting world Jewry as a profound expression of global Jewish solidarity.

The responsibility of the State of Israel for world Jewry is an important expression of the fact that Israel is not an ordinary democratic state, but also a "Jewish state." Though we may be divided by geography and citizenship, Israeli and American Jews—and their brothers and sisters around the world—are members of one nation.

Thus, it is imperative for the State of Israel to distinguish between citizenship and nationality. Israeli Jews and Israeli Arabs share a common citizenship. They are both Israeli, and are therefore entitled to and must be accorded the same civil rights. But they are not members of the same nation.

Nationality, according to the Israeli Supreme Court, is derived from objective traits such as religion, culture, and collective historical memory. This is another manifestation of the puzzle of identities characterizing the Jewish nation state. As a country that holds itself as both a democracy and the homeland of the Jewish people, debates will continue as to who is a Jew and who is an Israeli. What matters most is that we approach these debates in a respectful and consistent manner. The future of Israel depends on it.

Prof. Yedidia Z. Stern is Vice President of Research at the Israel Democracy Institute and a professor of law at Bar-Ilan University. Jay Ruderman is President of the Ruderman Family Foundation.