This reference for a preliminary ruling raises for the first time the question of the extent of the discretion available to the Member States to determine who their nationals are. In so far as citizenship of the European Union, which depends, admittedly, on enjoyment of the status of national of a Member State, is established by the Treaty, can the powers of the Member States to lay down the conditions for the acquisition and loss of nationality still be exercised without any right of supervision for Community law? That is, in essence, the point at issue in this case. This case therefore calls for clarification of the relationship between the concepts of nationality of a Member State and of citizenship of the Union, a question which, it need hardly be emphasised, to a large extent determines the nature of the European Union.

Read carefully: A Community national leaves his or her home state (the ‘first country’) to work in a host member state (the ‘second country’). While in the second country, he or she exercises the right to family reunification with a spouse, partner or dependent who is not a national of any EU or EEA member state (a ‘third-country’ national). When the Community national returns to the first country together with the family member, what determines the family member's right of residence in the first country? Community law – in which case the Community national would continue to enjoy the right of family reunification as before? Or the national immigration law of the first country, which could potentially dictate more restrictive conditions for family reunification?