Claims are periodically voiced against the Citizenship and Entry into Israel Law (Temporary Order) that prohibits the entry into the Green Line of Palestinians in order to reunite with their Arab spouses living in Israel. The law was legislated in 2003 and ahead of its (annual) renewal, there are those calling for its annulment due to its supposed discriminatory nature. This paper examines the justifications for preventing family reunification and demonstrates that unlike the approach of the Supreme Court which bases its support for the law solely on grounds of security, the demographic justification – preserving a stable Jewish majority – also bears not insignificant weight. This study presents the foundation of this justification – the legitimate existence of the nation state. The discussion of this illustrates the importance of the Nation State Law as providing validation for the various means of defending the State of Israel as the nation state of the Jewish People, including, preventing family reunification.