Again, these cases and the legal arguments that go into them really affect people's lives, and it's interesting to see how the different circumstances of a person can affect which side of the line they fall on.
As a recap, in Zambrano the question was how far EU citizens can rely on their EU citizenship rights in the Member State of their own nationality, when they have never moved to another Member State. The judgment was vague so I outlined two models of citizenship: either relying on EU citizenship in your own country is only available as an option where you've either used your free movement rights before or where you might be prevented from using them effectively in the future ("Back to the Future" model; or you have a right to reside in your own Member State independent of your national citizenship,* and therefore you can rely on EU citizenship simply if EU law applies to EU citizens in those cases. This second option means that Member States can't discriminate against their own citizens so that EU citizens are treated better than their own nationals ("reverse discrimination").
[* Member States control who gets their citizenship, and therefore who gets EU citizenship deriving from this.]
The problem in the McCarthy case is pretty much an issue I raised with the Back to the Future model (because I knew the case was coming up, and I know people the senario has affected in real life [for want of a better term]):
"Under UK law if a British national marries a third country national and wants to bring them home to the UK, and they haven't used their EU free movement rights, then they have to pay to get them into the country. So other EU nationals and British nationals who have used their free movement rights have preferential treatment over British nationals who never used their free movement rights. It is unlikely that, under the Back to the Future model, that that British citizen could claim that they wouldn't be able to use their EU rights effectively in the future if their spouse couldn't join them in the UK, so they wouldn't be covered by EU citizenship law."
This is essentially what happened to McCarthy, who had never left the UK, nor been a worker under EU law. She applied for an Irish passport, which she got, and tried to assert her EU citizenship rights (based on her Irish citizenship) to bring her spouse from a third country (not an EU citizen himself) into the UK to live with her. Could she rely on her EU citizenship?
Though I stated that I thought the Court was using the "Back to the Future" model in Zambrano (the reasoning was vague), I thought that over time the Court would become more explicit in its reasoning and follow the separate right to reside reasoning. So I thought 3 outcomes were possible, in order of desending likelihood:
1. She could, because she had Irish citizenship, and therefore she could be said to be living in a Member State of another nationality despite never having moved. That she only applied for the Irish citizenship so this would be the case ("cherry picking" her legal rights in the words of Advocate General Kokott) doesn't matter as there is nothing wrong in making use of legal rights made available to you. This would not concern the Zambrano decision.
2. She could not rely on the Citizens' Directive (2004/38), because she is a national of the the UK. However, she has a right to reside due to her EU citizenship regardless of having such a right due to her nationality, and therefore the UK could not discriminate against her compared to EU citizens of non-UK nationality if they are in the same position. [Explicitly adopting the reasoning of AG Sharpston in the Zambrano case that was implicitly, but not clearly, endorsed].
3. As 2, but referring to the vague idea of the substance of EU citizenship rather than reasoning clearly. So as in Zambrano.
What the Court actually did, was rule that she did not have the protection of EU law as a citizen as she was a national of the Member State and had not exercised any free movement rights. Her Irish citizenship was irrelevant, and, in fact, there is no right of residence separate from the exercise of free movement rights. In other words, there is only the Back to the Future model.
To quote the Court (skippable if you're not interested in the technical legal reasoning of the Court):
"39 Hence, in circumstances such as those of the main proceedings, in so far as the Union citizen concerned has never exercised his right of free movement and has always resided in a Member State of which he is a national, that citizen is not covered by the concept of ‘beneficiary’ for the purposes of Article 3(1) of Directive 2004/38, so that that directive is not applicable to him.
40 That finding cannot be influenced by the fact that the citizen concerned is also a national of a Member State other than that where he resides.
41 Indeed, the fact that a Union citizen is a national of more than one Member State does not mean that he has made use of his right of freedom of movement.
The applicability of Article 21 TFEU
47 Indeed, the Court has stated several times that citizenship of the Union is intended to be the fundamental status of nationals of the Member States (see Case C‑34/09 Ruiz Zambrano  ECR I‑0000, paragraph 41 and case-law cited). Furthermore, the Court has held that Article 20 TFEU precludes national measures which have the effect of depriving Union citizens of the genuine enjoyment of the substance of the rights conferred by virtue of that status (see Ruiz Zambrano, paragraph 42).
49 However, no element of the situation of Mrs McCarthy, as described by the national court, indicates that the national measure at issue in the main proceedings has the effect of depriving her of the genuine enjoyment of the substance of the rights associated with her status as a Union citizen, or of impeding the exercise of her right to move and reside freely within the territory of the Member States, in accordance with Article 21 TFEU. Indeed, the failure by the authorities of the United Kingdom to take into account the Irish nationality of Mrs McCarthy for the purposes of granting her a right of residence in the United Kingdom in no way affects her in her right to move and reside freely within the territory of the Member States, or any other right conferred on her by virtue of her status as a Union citizen.
50 In that regard, by contrast with the case of Ruiz Zambrano, the national measure at issue in the main proceedings in the present case does not have the effect of obliging Mrs McCarthy to leave the territory of the European Union. Indeed, as is clear from paragraph 29 of the present judgment, Mrs McCarthy enjoys, under a principle of international law, an unconditional right of residence in the United Kingdom since she is a national of the United Kingdom.
51 The case in the main proceedings also differs from Case C‑148/02 García Avello  ECR I‑11613. In that judgment, the Court held that the application of the law of one Member State to nationals of that Member State who were also nationals of another Member State had the effect that those Union citizens had different surnames under the two legal systems concerned, and that that situation was liable to cause serious inconvenience for them at both professional and private levels resulting from, inter alia, difficulties in benefiting, in one Member State of which they are nationals, from the legal effects of diplomas or documents drawn up in the surname recognised in the other Member State of which they are also nationals. [Own note: so EU law only applied since national law might prevent EU citizens from using their EU rights in the future].
53 Thus, in Ruiz Zambrano and García Avello, the national measure at issue had the effect of depriving Union citizens of the genuine enjoyment of the substance of the rights conferred by virtue of that status or of impeding the exercise of their right of free movement and residence within the territory of the Member States.
54 As stated in paragraph 49 of the present judgment, in the context of the main proceedings in this case, the fact that Mrs McCarthy, in addition to being a national of the United Kingdom, is also a national of Ireland does not mean that a Member State has applied measures that have the effect of depriving her of the genuine enjoyment of the substance of the rights conferred by virtue of her status as a Union citizen or of impeding the exercise of her right of free movement and residence within the territory of the Member States. Accordingly, in such a context, such a factor is not sufficient, in itself, for a finding that the situation of the person concerned is covered by Article 21 TFEU."
There may still be some cases where EU citizens can rely on their Union citizenship against their own Member State on grounds of non-discrimination, but this makes it extremely difficult to argue if the Court refuses to acknowledge the significance of your Union citizenship in the first place. The judgment makes clear that in Zambrano the decisive factor was that the Union citizens would be required to leave the territory of their home country, and that of the whole Union as they were young children dependent on their non-EU national parents. We still don't know what the new idea of "substance of EU citizenship rights" is, but it doesn't mean what we thought it might mean - the Civis Europeus Sum that a more rational, unified idea of citizenship might bring.
It's obvious that the law on citizenship is messy - and, in my opinion, highly unsatisfactory. It is difficult for citizens to know when they are protected, and when they are not - and sometimes it can be based on a tiny detail of their life or how they might lead their life. Whether children are involved or not can also be a factor - perhaps this shows a certain sentimentality of the Court that it tries to rationalise through its case law. In any case, McCarthy is a blow for those supporting a more equal citizenship.
**(As an aside, the Court referred to Article 21 TFEU rather than Article 20 as it did in Zambrano - since they repeat each other to a certain extent makes the relevance unclear, but it's a debate best left to academic literature rather than this blog post).**