GLOBALCIT Review Symposium on Ana Tanasoca, The Ethics of Multiple Citizenship, Cambridge University Press, 2018



Ana Tanasoca, Macquarie University

I thank the reviewers for their commentaries. They contain many interesting points, many of which will serve to push the debates forward. I will not try to answer each point in turn. I will simply try to pick up the ones of most importance to the central arguments of my book and, hopefully, the ones of the most general interest.


Let me begin by standing back from those specific comments to reflect upon the nature of the importantly different scholarly enterprises in which we are engaged. These enterprises represent different callings, with different agendas and goals, which must be conducted differently. I do think that each—when conducted according to its own logic—can contribute to the overall study of multiple citizenship and cognate phenomena. There is thus value in concentrating on one level of analysis in its own right, instead of trying to do everything at the same time, which can easily lead to a mash-up that does not well serve any analytic aspirations.

In that spirit I welcome all suggestions for further empirical research of multiple citizenship suggested in the replies. However, I must emphasize that my book is an exercise in normative analytic political theory, which I take to be applied moral philosophy. Of course, political theorists can tailor their analyses to make them more or less abstract, drawing to a greater or lesser extent on empirical science; both of those approaches have their merits. My aim in this book was to develop a more abstract inquiry into multiple citizenship that could attract analytic political theorists and political philosophers to the topic, which has to date been dominated principally by legal and sociological analyses. Much of the existing work on multiple citizenship is guilty of the naturalistic fallacy, insofar as it seeks to derive ‘ought’ from ‘is’ – normative prescriptions from facts of sociology, law, or history.[1] My arguments should not be read fundamentally as empirical claims about the state of the world. Mine is not an exercise in law, political science, sociology, or history. Some of the book’s arguments do draw on other disciplines. But my basic analysis and proposals are largely driven by moral logic and that alone, at least in the first instance.

Many of the book’s arguments are exercises in ideal theory, which is laden with simplifying assumptions. Some of the proposals of this book will of course have to be adjusted to non-ideal aspects of the real world. We would need to build in some transitional arrangements for migrants as they move and for states as they move toward implementing some of the proposals. But those are special, peripheral issues, not central ones. And they are best bracketed, in the first instance, to get a clear view of what is most centrally morally at stake. Trying to build all the complexity of the world into your model from the start, it is no surprise that one ends up just reproducing the world as we know it. And this is not, I think, because our world is already the morally best one of all possible worlds, but merely because we’re having trouble envisaging alternatives with all the clutter blocking our view of better possible worlds.

Finally, much of my book is devoted to scoping out logical possibilities and mapping justifications for various policies. That is what I am doing, for example, when discussing what would be the second best to a first-best world in which there are no borders or everyone is a multiple citizen, or what could justify sending states depriving their expat dual citizens of its citizenship or merely their political rights. That is part and parcel of an exploratory theoretical inquiry; it does not commit the author to any particular view.

Where my normative prescriptions rest in part on empirical assumptions, further testing of those assumptions would always be good. Just notice, however, that one or two empirical studies (such as those typically cited by the commentators) can never really be conclusive, even where they are on-point. They sometimes miss what is the crucial point in my analysis; and in at least one case the empirical study (Vink et al.’s) a commentator (Bauböck) cited contains no discussion whatsoever of the claim for which it was being cited.[2]

The central focus of the book is inquiring into the possible shortcomings of multiple citizenship, the causes of these shortcomings, and potential remedies (like the unbundling). I admit of course (and acknowledged as much in the book) that implementing the unbundling of citizenship rights proposed in chapter 8 might present several expected and unexpected challenges; my analysis of the unbundling is exploratory, and some fine-tuning might be needed. But what I would emphasize here, methodologically, is that the unbundling proposal is merely the result of taking the arguments about multiple citizenship to their logical conclusion—which is, that rights should be severed from citizenship, while personal choice be given a more central focus in citizenship policies. Developing the moral arguments that justify the unbundling proposal, rather than elaborating the unbundling proposal as a fully formed legal or policy instrument, remains the central focus of the book. Others with complementary expertise will of course be better positioned to fine-tune the legal and policy implications of my proposal, or to propose their own alternatives in the same spirit.


Most fundamentally, my book criticizes multiple citizenship on the grounds that it is not progressive enough. I can see how that might seem odd considering the current political context. But I am not a sociologist, historian, or commentator on current affairs. Moreover, recent setbacks mentioned by Seubert in a few countries (US, Germany) over the last years do not reverse more general, global trends over longer periods of time, such as the increasing acceptance of multiple citizenship by states. Seubert mentions the promotion of dual citizenship for external kin minorities as a problematic trend. I agree but hasten to add that that is only further evidence of the increasing acceptance, rather than dismissal, of dual citizenship. I disagree with Seubert however in that I do not think that people currently have an equal and fair access to dual citizenship irrespective of their country, birth circumstances, class, and income. This is due to jus sanguinis and jus soli (not to mention investment) operating as grounds of acquisition of a second citizenship. In the book I pointed out how the first may lead to the accumulation of birth advantages and how the second may lead to unequal access to a second citizenship for the poorest who cannot afford to migrate, either legally or illegally. Of course, other factors like restricted access to regularization, strict naturalization requirements, and the risk of deportation (see the US, for example) may also prevent the globally worse off from becoming dual citizens. My point is not that the global elites are the only ones to hold dual citizenship, but that those better off will have increased access to it while those worse-off may have trouble accessing dual citizenship to the same extent. In part this is also due to the fact that some of the poorest countries in the world still prohibit dual citizenship, as discussed in chapter 7.

Second, Seubert points to Germany’s refugees and working migrants holding dual citizenship as proof that the global elites are not the only ones to benefit from dual citizenship. Fair enough. But Germany’s example is just that—the case of one country only. It’s worth asking ourselves just how well Germany’s example generalizes globally. A quick look at the present global political landscape may indicate a rather grim answer. Third, the fact remains that we would need extensive data from a multitude of states in order to be able to establish whether, within any given state, those who are better off income-wise do indeed have an advantage over their worse off co-nationals in accessing dual citizenship. And last, regarding citizenship and the desire of parents to transmit their history, culture, or political ideals to their children, I take it that those goods can be perfectly well transmitted through socialization alone even in the absence of a common passport, especially in a globalized and increasingly multicultural world. One’s passport does not constrict one’s culture, only one’s rights.

Regarding citizenship-sine-political rights: it is mentioned as a logical possibility, and in relation to various boundary principles discussed in chapter 6. Nothing in that discussion denies that, as a current matter of fact, political rights are a central element of citizenship or that political rights may influence the enjoyment of other rights. Indeed, my argument regarding the implementation of the unaffected interests principle relies on this connection between political and other types of rights as one source of affectedness. In mapping out logical possibilities when discussing the implementation of the unaffected interests principle, I envisage a scenario where political rights are allocated to some individuals without allowing them to hold other categories of rights, so that in exercising those political rights they would not be able to shape their own rights-entitlements. This would allow those individuals to decide on matters that would not impact their interests at a later date—making them unaffected decision-makers, as the principle requires.

Regarding the nature of legal rights, there is no reason to think that rights cannot be conceived as goods to be distributed. Indeed, they do get distributed all the time by states to people when they naturalize and, in the past, to women and formerly-oppressed groups with the extension of franchise and civil rights. Sure, there are various grounds and normative justifications for these distributions, among them reciprocity and fairness as Mantha-Hollands points out.

With regard to the ways in which multiple citizenship can undermine collective reasoning, the theoretical argument in chapter 5 is premised on the political participation of dual citizens. As acknowledged there, the various political science studies we have on dual citizens’ political participation provide mixed results (see pp. 87–8); but my point is that the results are mixed, and enough of them participate to make the discussion of the chapter of practical importance. My aim in that chapter was to discuss the mechanism by which multiple citizenship might become problematic from a democratic perspective. The arguments I advance are theoretical but draw on empirical research. I cast some doubts regarding dual citizens’ ability to systematically and reliably reformulate their preference orderings to fit each of the political frameworks of their multiple communities. Since there is no empirical research testing these matters directly[3], I merely point out why and how this is an empirically plausible hypothesis deserving of further examination.

Of course, competing frames of reference can exist among diaspora communities in the absence of multiple citizenship, as Mantha-Hollands notices. But my argument was never that multiple citizenship creates these competing frames, but rather that, by enabling the exercise of voting rights, multiple citizenship may impact the coherence of collective decisions in a negative way, taking into account a diversity of frames. The issues I mention arise from the exercise of political rights and thus do not apply to diasporic communities in the absence of citizenship. Mantha-Hollands argues that, empirically, mono-nationals have trouble seeing the big picture anyway. This is not an issue for my argument; quite the contrary, if she is right then this just makes dual citizenship even more problematic, since the danger of reaching incoherent collective decisions increases with the proportion of voters having non-singled-peaked preferences. If a larger proportion of mono-citizens’ preferences are already non-singled-peaked, adding more people whose preferences are likely to be non-single-peaked only makes things worse. In this case, even if only modest numbers of dual citizens vote (as Mantha-Hollands argues it is empirically the case), this could be enough to undermine collective rationality. Together, her two objections to my chapter 5 only serve to strengthen the modest argument I offer there.

As with Seubert, Mantha-Hollands argues also that my claim about the global elites having privileged access to multiple citizenship is ‘empirically flawed’ because many individuals from lower and mid-income countries (like Morocco, Albania, Turkey and India) hold dual citizenship. Yet many of the world’s poorest countries still ban dual citizenship, as pointed out in chapter 7. Furthermore, as this chapter makes clear, intra-states comparisons are not enough when talking about global inequality. As my examples illustrate, when talking about global elites or the global poor I am talking about individuals, not states. The relevant distinction is not between higher-income and lower-income countries, but rather between worse-off and better-off individuals within each state. Even lower-income states have their plutocracies.

Of course, what benefits and burdens dual citizenship entails varies depending upon what countries we are talking about. Mantha-Hollands complains that I treat dual citizenship as a homogeneous category, when dual citizenship entails different sets of opportunities for different individuals who are dual citizens of different countries. As explained in my general response above, my aim, as a normative political theorist, was not to catalogue these differences in detail but rather to develop a theoretical moral analysis of this phenomenon that abstracts from all those differences. That is what is most sorely missing from current discussions.

As regards double taxation agreements, I do not think that dual citizens are complete free-riders. I merely point out that currently double-tax agreements are set up in a way that may allow them to free-ride with respect to particular types of income offered by their poorer sending states. Importantly, ‘free-riding’ is used in a descriptive rather than normative sense. My book is not a manual of personal ethics but rather discusses multiple citizenship primarily from the perspective of the policy- and law-maker.

Notice also that reforming tax agreements does not necessarily entail increasing the overall tax burden on dual citizens. I do not argue that dual citizens should pay full income taxes in both states. The reform I propose would not require dual citizens to pay more taxes in total but would instead merely reallocate the taxes they pay between the two states of which they are citizens. Currently what double-tax agreements do is prevent both states from taxing the same category of income. But they do that by advantaging the (typically richer) state of residence in allowing it to tax even some categories of income generated in other (typically poorer) state. The double-tax agreement reform I propose would merely decide each state’s tax claims by taking into account a concern for global inequalities so as to give a stronger claim to the poorer of the states. The cost would thus be borne by the richer states which would have to reduce their tax intake, rather than by the dual citizens themselves; the reform would not require them to pay more in taxes but merely redirect the tax they pay on some categories of income to a different state than at present, that is, to the poorer of their two states.

My sole concern in chapter 7 is global inequality. I discuss multiple citizenship from this particular perspective and propose the reforms there with this concern in mind. Some might disagree that global inequality deserves such attention, in which case chapter 7 will disappoint them. My point is simply that if our primary concern is with global inequality (which may of course not be insofar as there are other morally relevant considerations which some may want to prioritize), then double-taxation agreement should be reformed in a way that would give priority in taxation to the poorer of a dual citizen’s two states. Regarding the multiple citizenship levy that I discussed as a less feasible alternative to double taxation agreement reforms, I doubt that it would make many renounce their citizenships—so long as the levy is a sufficiently modest one, as I proposed.

Jo Shaw is right that the book leaves unanswered several questions. There is no dedicated discussion to what ethical citizenship entails or how the boundaries of a political community should be drawn. It is true that my views on the moral values underpinning citizenship only emerge slowly as the chapters progress. A conception of ethical citizenship is missing—to some extent intentionally, because I conclude the book by arguing in favour of a more flexible conception, separately allocating the various categories of legal rights that currently comprise citizenship. But there are many ways in which multiple citizenship may be reformed so as to bring it more in line with some of the moral considerations discussed. A greater emphasis on personal choice (when it comes to naturalization but also citizenship retention) is one that I float, as Shaw points out.

With respect to the boundaries of a political community and the allocation of political rights, a rich philosophical debate already exists on these issues. Besides the two main principles that we already have (the legally subjected and the affected interests principles), the proximity principle discussed by Jeremy Waldron may also be useful, particularly when thinking of who should get a vote on matters which are prone to repeatedly create conflicts among the much same people.[4]

The points about active citizenship that Shaw raises are very interesting. What is puzzling about article 44 of the Australian Constitution is that it extends to cases where one is merely entitled under the law of another state to the citizenship of that state, even if one is actually not recognised already by that state as a citizen, even if one has never applied for citizenship or been granted one there, even if one is not even aware that one might be entitled to citizenship there, and so on. Thus, under article 44, one need not actually be a dual citizen to be prevented from occupying public office. In the case of Begum as well, the mere fact of potentially being entitled to Bangladeshi citizenship does not make her a Bangladeshi citizen, hence the UK’s decision effectively rendered her statelessness and violated her human right to citizenship.

Both cases represent morally (and perhaps even legally) problematic interpretations of dual citizenship that completely overlook individual agency and personal choice. A concept of active citizenship might be useful if adopted domestically by states, especially if it would place greater emphasis on individual choice. In international law, the doctrine of ‘effective nationality’ and the principle of ‘genuine connection’ asserted by the International Court of Justice’s decision in the Nottebohm case goes some way in that direction. Nottebohm recognises citizenship as a ‘legal bond having at its basis the social fact of attachment, a genuine connection of existence, interests, and sentiments, together with the existence of reciprocal rights and duties.’[5]

On the other hand, some have warned that the genuine connection test increases the discretion of officials and it may unfairly deprive individuals of their entitlements if the test is too thick.[6] Similarly, we may have doubts whether a test of active citizenship, when put in the wrong hands, would do any good. Would it have changed anything in Begum’s case? It depends of course on the influence personal choice (and interpretations of it) would have on deciding what counts as ‘active citizenship’. That being said, the concept could play an important role in defending the right moral entitlements of individuals, provided it is adopted with this primary purpose in mind. A philosophical discussion of choice, luck, and what counts as free will would have to be essential components of these further debates.


Sadly, Rainer Bauböck’s comments almost invariably misread or distort my views and even fabricate some to which I do not subscribe (especially concerning chapters 5 and 7). I will not try to correct all of those misrepresentations here. There are simply too many; it would try the reader’s patience (as well as my own). I will here address just enough of them to demonstrate beyond doubt that readers need to work through the book for themselves, rather than relying on Bauböck’s tendentious gloss and critique.

Some of Bauböck’s objections may arise from a more general misunderstanding of the nature of the very different enterprises in which we are each engaged. Bauböck, for example, identifies a ‘rights-ex-machina’ fallacy that he claims is ‘quite common in liberal normative theory’; and he complains that that overlooks how rights come attached to citizenship, and not the other way around. If by this Bauböck means (as seems to be the case) that citizenship should entitle people to all and only the rights that it currently does, then this counts as a clear example of the naturalistic fallacy. As I said at the beginning of this rejoinder, this is a basic failing of so many analyses of (multiple) citizenship: fallaciously deriving ‘ought’ from ‘is’.

In any case, Bauböck simply misses the point that the aim of normative analytic political theory is to inquire whether, logically and morally, rights are or are not inseparable from citizenship. My conclusion on the basis of the arguments developed in this book is that they are logically separable and, indeed, that there may be a good moral case for separating them. Considering the many obstacles to immigrating to a better place and then acquiring another citizenship through naturalization there – obstacles which may deprive so many of what should be morally theirs – wouldn’t it be better to have an additional system by which states more easily and readily grant individuals different categories of legal rights (e.g., residence, free movement, work rights, diplomatic protection etc), creating custom-made constellations of rights or ‘denizenships’ that also go some way towards acknowledging that individual as part of that community? I acknowledge, as I did in chapter 8, the huge bureaucratic pressure this would put on states. But nobody said morality is not, or should not be, demanding of states or individuals. While they may not have this capacity now, states could try to develop such a capacity little by little in the future. In any case, matters of feasibility should not be seen as constituting the last word in moral matters. Like human rights, ideal theory more generally can serve aspirational purposes and as a pointer to what we should try to accomplish in the future, even if the ideal is not fully attainable in the non-ideal circumstances that presently prevail.[7]

Something similar could be said about Bauböck’s complaint that states cannot give up the category of citizenship as we know it ‘without ceasing to be states’. While the book argues that citizenship as we know it should continue to exist for good reasons, I do not see (nor does Bauböck give) any reason whatsoever for regarding classic citizenship as necessary for statehood. States must exercise permanent jurisdiction over a territory and that must be recognised by the other states, true. A state must also have a population to support state institutions and a national economy. But long-term resident migrants, who already support the economy through their labour and taxes political rights, can help meet that population requirement. The Montevideo Convention (which has been ratified by only 16 states, note!) specifies a ‘permanent population’, a term Bauböck emphasizes. But a ‘permanent population’ need not be composed of the same individuals: after all, people are born and they die, so inevitably a political community will consist in different people at different points in time. Does this ‘destabilize’ the state? Luxembourg’s population is composed of 48 percent non-nationals: is Luxembourg not a state? Citizenship is useful because in principle it establishes which state should take responsibility for each individual and provide a series of benefits including diplomatic protection and a place on this Earth where one is always welcome and safe. I can see how one might be worried about a democratic deficit that would occur with constant reshuffles of states’ populations, if people can exercise their political rights in one place and then leave, while others will have to bear those consequences at a later date. However, some such deficit is built in through birthright citizenship which ensures that those born tomorrow will be ruled by constitutions and laws adopted long ago, having nonetheless a chance to change them in the future. Some people vote and some do not in each election, so each government represents the very same nation and yet it was elected by different configurations of voters.

Bauböck complains that I do not acknowledge that jus soli and jus sanguinis have existed before the international state system. Wrong: see the very first footnote of the book, on page 17. When talking about efficacy concerns, I have in mind the ‘universal adoption of jus soli and jus sanguinis’ (see p. 21), based on other scholarly studies I reference there. He might not agree with those studies, but his reply gives no reasons for questioning them.

Bauböck argues that ‘automatic and lifelong’ citizenship is necessary for states to ensure a permanent population and ‘the intergenerational continuity that allows them to take decisions which will shape the conditions of future generations’ lives’. Unless automatic long-term citizenship is seen as an ‘entrapment strategy’ meant to keep people in place and preventing them from moving elsewhere (which I don’t see as democratic at all), I do not see analytically why this should be the case. After all, it is legal jurisdiction over a territory that enables states to affect all those who happen to reside or travel on that territory, citizens and non-citizens alike.[8] Furthermore, if a state is so bad in terms of its institutions and conditions that everybody there wishes to go elsewhere, would the disappearance of that state upon the departure of all its residing population be morally regrettable? Bauböck may think so, if he sees the survival of states and the Westphalian state system as valuable in itself. Many political theorists would disagree: states and the Westphalian system are valuable for the benefits they can ensure for individuals and communities; they exist to serve people, not the other way around.

Regarding naturalization, Bauböck claims that I support automatic loss of citizenship upon naturalization then wonders why I adopt a softer stance that accepts dual citizenship but requires individuals to actively choose their citizenship. Again, I think this is due to a misapprehension of the entire nature of my discussion. Chapter 3 discusses various arguments for and against a citizenship renunciation requirement for dual citizens; various justifications are considered and options examined, all in an exploratory spirit. To ‘consider’ an option is not to ‘advocate’ it; to ‘explore’ an option is not to ‘adopt’ it. Overall, I am doubtful of any restrictions of dual citizenship via naturalization and conclude that dual citizenship via naturalization is problematic only insofar as it does not arise from an active, reflective choice.

Bauböck wonders why states allowing dual citizenship to begin with, as a way of maintaining ties with their emigrants, would ask them whether, on reflection, they wish to retain their citizenships there. The answer is easy: because allowing one’s membership in a political community to be actively chosen is respectful of individual agency of those with whom the community wishes to maintain ties. But that Bauböck even asks the question is in itself mind-blowing: does Bauböck seriously take what is morally right to be a matter of what states are prepared to do? Surely the fact that something is in a state’s interest does not make it morally right (see also my discussion from chapter 2).

Needless to say, I do not see automatic loss of citizenship as the first-best option, as Bauböck alleges. One reason is that that would entail a default rule which precludes individual choice (I argue extensively against such default rules in chapter 3). Another reason is that one can be morally entitled to same categories of rights in multiple states, as pointed out in chapter 8. The first-best option discussed in that chapter is a system of citizenship renewal, which would allow individuals to keep citizenships in multiple states, while at the same time allowing them to reassess from time to time their memberships in those places, reassert their consent, and renew their political contract with those states. Relationships that are based on explicit consent are in my view morally superior to those that are not—and political relationships are no exception.

Bauböck argues that I ‘suggest that immigrants should not be naturalised without being screened for cultural and political assimilation’. Here Bauböck (like Trump, quoth Obama) is ‘just making stuff up’. Chapter 5 merely presents a theoretical argument for why exercising voting rights in multiple states might be problematic. It does not call for the extreme measures Bauböck mentions. It only makes us reflect on one particular ground on which double voting might be problematic (which is consistent with it being legitimate on other grounds that are more important), and think of ways in which voting rights can be decoupled from certain sorts of citizenship.

In discussing the consequences of dual citizenship for global inequality, I argue for a reform of double-taxation agreement that would advantage the poorest of a dual citizen’s states by allowing it to tax more income streams. This just means that the (richer) state of residence would get to tax fewer categories of income that presently. It’s obvious that the chapter does not argue in favour of outlawing dual citizenship as Bauböck himself ‘outlandishly’ claims; it merely argues in favour of a fairer distribution of taxation claims so that richer states of residence can no longer tax even revenue originating in other poorer states. The scope of the prioritarian clause applies only to some categories of income that two states have a claim to tax (see pp. 130-42), not to all types of income. Where the same state is both the state of residence and the state of source, double-tax agreements do not apply. So the prioritarian clause would not stop richer states from taxing income originating on their own territory.[9] As made clear on p. 149, the prioritarian clause covers cases where one has ‘income in one state but residence in another’.

Bauböck asks: why rich states would agree to forego revenue by letting poorer states tax their dual citizens’ income? He proposes, instead, that the rich state be allowed to collect those taxes but then use those revenues for development assistance. Bauböck’s very question, here once again, conflates right with might, reducing what is morally right to what states would be prepared to do. His counterproposal marries that morally outrageous proposition to a pragmatic contradiction. Why would a richer state that refuses to cede tax authority over those revenues to the poorer state, on the grounds it is not willing to forego those revenues, then be willing to transfer those very same revenues to the poorer state as development assistance? If they would be willing to use their revenues for development assistance to fight global inequality, I don’t see why they wouldn’t, for the same reason, be willing to let the poorer state attract more revenue through tax.

States’ motivations apart, there are good moral reasons to prefer reform of double taxation agreements to development aid. Global justice theorists have discussed at length the ways in which development aid and money transfers from rich to poor countries can be morally problematic, creating unequal moral relationships where poor states are treated as passive beneficiaries of others’ charity. Reforming the OECD Model Tax Convention would put these states in an empowered position where they would be able to exercise their tax authority, asserting their sovereignty in a way development aid could never ensure. Given that the vast majority of bilateral dual taxation agreements are based on the OECD Model Tax Convention, and given that there is a committee within the OECD tasked with assisting developing countries which might hopefully be willing to lobby for reform in this direction, there might be some realistic hope for some such reform to succeed.


Notes to this response:

[1]Including personal history: we must be aware of what Calhoun calls the ‘class consciousness of frequent flyers’. See Craig Calhoun, ‘The class consciousness of frequent travellers: towards a critique of actually-existing cosmopolitanism’, Conceiving Cosmopolitanism, ed. Steven Vertovec and Robin Cohen (Oxford: Oxford University Press, 2002), pp. 86-109.

[2] Maarten Vink, Arjan H. Schakel, David Reichel, Ngo Chun Luk and Gerard-René de Groot, ‘The international diffusion of expatriate dual citizenship’, Migration Studies, forthcoming, doi:10.1093/migration/mnz011. Bauböck claims, ‘New research by Maarten Vink and others (2019) shows, however, that there is virtually no correlation between the likelihood that a country of origin tolerates dual citizenship among its emigrants and its GDP per capita’. But while Vink et al. use GDP per capita as a control in one of their models, they omit reporting that variable when reporting the results of Model 4 in Table 1; neither do their Supplementary Materials report either the first-order correlation between GDP per capita and probability of accepting dual citizenship or how that variable interacts with the other variables in Model 4.

[3]I.e., there are no experimental studies showing how deliberating and voting in two different groups with two different frames of reference might affect single-peakedness and collective decision-making.

[4]Jeremy Waldron, ‘The principle of proximity,’ New York University School of Law, Public Law and Legal Theory Research Paper Series, working paper no. 11-08, January 2011.

[5] Nottebohm (Liechtenstein v Guatemala) [1955] ICJ Rep 4, at 23.

[6]For a discussion along these lines, see Rayner Thwaites, ‘The life and times of the genuine link’, Victoria University of Wellington Law Review, 49 (2018), 645-70.

[7]See Holly Lawford-Smith, ‘Understanding political feasibility’, Journal of Political Philosophy, 21 (2013), 243-59.

[8]Indeed, as Weber points out, the fundamental characteristic of statehood is the monopoly on the legitimate use of force over a territory.

[9]But see Mathias Risse and Marco Meyer, ‘Debate: tax competition and global interdependence’, Journal of Political Philosophy, forthcoming, for an argument that states are not entitled to the proceeds of taxing national income.