The most parsimonious definition of the term is "membership in a political community." Since most of us live in democracies these days we like to think of citizenship as an association that we choose freely whether we stay in our country of citizenship all our lives or move outside its borders temporarily or permanently.
Nothing could be farther from the truth. Birthright citizenship is ascriptive. This means that human beings are basically sorted into nation-states based on criteria that they have no control over: place of birth (jus soli) or bloodline (jus sanguinis). This sorting occurs at birth and the status of citizen follows that person for a lifetime unless he or she takes on another citizenship and formally renounces.
Different nation states have different rules for how they define their citizenry - transmission by jus soli, for example, may be limited in one country and completely open in another - but the essential fact we all should grasp is that it is the state that does the sorting, not the individual.
This distinguishes the state from most other forms of human association, including the family, which is founded upon a voluntary act - marriage. It also flies in the face of the modern state's own constitutive ideology of contract and consent, articulated in the political philosophy from Hobbes to Rousseau. (Christian Joppke in Citizenship and Immigration).It is a prerogative that states guard jealously. If a French, Mexican, Chinese citizen moves to the U.S. and decides to become a U.S. citizen and does so by swearing the Oath of Allegiance:
"I hereby declare, on oath, that I absolutely and entirely renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty of whom or which I have heretofore been a subject or citizen; that I will support and defend the Constitution and laws of the United States of America against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I will bear arms on behalf of the United States when required by the law; that I will perform noncombatant service in the Armed Forces of the United States when required by the law; that I will perform work of national importance under civilian direction when required by the law; and that I take this obligation freely without any mental reservation or purpose of evasion; so help me God."
We should all understand that this "renunciation" is not at all valid from the perspective of the sending country. France, China and Mexico will continue to see this person as legally "one of us" and the new American citizen will still have formal citizenship status in that state until he goes through some sort of renunciation/relinquishment process.
The U.S. government itself does exactly the same thing. An American who takes on British citizenship and swears an oath to the Crown does not lose American citizenship automatically - he or she will only lose US citizenship by informing the US government that he took on British citizenship with the intent to relinquish US citizenship. If he does nothing then he is a dual and is claimed by both.
Furthermore since so many nation-states today have mixed citizenship transmission regimes (jus soli AND jus sanguinis) the original state may claim the children (and sometimes even the grand-children) of the emigrant even if they do not live in the home country of their parents, may not speak the language, and have no other ties to the original state other than blood.
This state of affairs has been exacerbated greatly by international migration and there are some serious consequences to this clash between state citizenship law and globalization.
The first is obvious - the dramatic increase of dual nationality. In fact, we are entering an era where it is probably more accurate to say "plural nationality" since it is becoming more and more common to see children with 3 or more passports.
Another is that citizenship as status no longer correlates precisely with citizenship as identity. Just because someone has a U.S. passport does not mean that he feels American or has any real ties to that country. For him it may simply be a travel document that is required if he wishes to visit the United States - be aware that it is US law that all US citizens must enter the US with a US passport even if the person does not consider himself to be an American. That, I think, shows very clearly that citizenship as status is not up to the individual but is decided by the state in question.
In fact, formal citizenship status in a second state may come as a complete surprise to the person concerned. A second-generation immigrant may be completely unaware that he is, in fact, a dual national. In countries with large numbers of immigrants like the U.S., Canada, France and Australia, a person born to immigrant parents or grand-parents may be completely oblivious to the fact that he is (or could be) a formal citizen of one or more other countries.
For countries of immigration this is a serious issue that they prefer (for now) to ignore. As citizens of another state it is much easier for the children or grandchildren of immigrants to reverse migrate back to the original home country. In the case of the EU, the possibility of obtaining a passport that opens the doors to 27+ states is very very attractive.
Sometimes the revelation that a person is in fact an involuntary dual citizen is an unwelcome bit of news. Since citizenship as status and citizenship as identity are seen as the same thing in many places, this status can lead to suspicion when it is revealed. This is especially true when it concerns a public figure - a politician, a government official, an intellectual, a leader of industry or a much-admired entrepreneur. Telling my French family that Anne Sinclair was an American evoked some very strong emotions.
Something very similar has happened recently in the American political area. The Texas senator Ted Cruz was recently "outed" as a dual citizen of Canada and the U.S. From the Dallas News:
"Born in Canada to an American mother, Ted Cruz became an instant U.S. citizen. But under Canadian law, he also became a citizen of that country the moment he was born.
Unless the Texas Republican senator formally renounces that citizenship, he will remain a citizen of both countries, legal experts say."
Does this mean that Senator Cruz is one of those "anchor babies" that politicians love to rail against? Was his American mother a "birth tourist"? Inquiring minds want to know.
What is clear is that his status as a dual will have an impact on his political career in the U.S. And that is a bit unfair. Ted Cruz didn't choose to be Canadian - he is an "accidental Canadian". In fact, he has made it very clear that he considers himself to be an American. Well, that's fine but his assertion of identity does nothing to change his citizenship status because it's not up to him. He has birthright citizenship from two countries - birth, not choice, made him a dual citizen - and that is not any of his doing. And now he must go through the formal process to renounce if he wishes to shed that birthright. That's just the way it works.
Personally, I find that there is something fundamentally wrong in the way birthright citizenship "works" in the 21st century. It's terrible for democracy since it makes "membership in a political community" an inherited status and leads to an aristocracy - something that should have no place in a democratic nation-state. In other cases it leads to the conferring of citizenship against the will of the person concerned - where is the explicit consent here? And it has real consequences (some of them very negative) for people caught entirely against their will in a state's net.
Allison Christian's recent post, Here is the Only Reason Ted Cruz's Citizenship is Interesting, eloquently explains how involuntary citizenship transmission methods coupled with the obligations demanded by modern states of citizenship have terrible consequences for more and more people in today's globalized world.
My firmly held belief is that the conferring of citizenship at birth is one traditional prerogative of the nation-state that should be wrested out of their hands and buried deep.
"But, it is plain, governments themselves understand it otherwise; they claim no power over the son, because of that they had over the father; nor look on children as being their subjects, by their fathers being so. If a subject of England have a child, by an English woman in France, whose subject is he? Not the king of England's; for he must have leave to be admitted to the privileges of it: nor the king of France's; for how then has his father a liberty to bring him away, and breed him as he pleases? and who ever was judged as a traytor or deserter, if he left, or warred against a country, for being barely born in it of parents that were aliens there? It is plain then, by the practice of governments themselves, as well as by the law of right reason, that a child is born a subject of no country or government." (Locke, Second Treatise of Civil Government.)"
I believe that what Locke wrote in 1690 is just as pertinent in 2013. Jus sanguinis and jus soli, if conferred without consent, are incompatible with democracy - it is the "consent of the governed" that is the root of legitimate political authority in today's world, is it not? These citizenship transmission practices --however convenient and useful (dare I say lucrative?) they are for the state- should be ended.
This would mean: no more aristocracies made up of birthright citizens; no more tyranny of birthright citizens over the naturalized and immigrants; and no citizenship without consent. Ever.