Over 2000 years ago Aristotle wrote that neither blood or place of birth should make one a citizen. It was the act of ruling and judging or being ruled as a member of a political community that made citizens, not an accident of birth.
Clearly Aristotle's argument did not have much influence because today almost every nation on this planet allows for the automatic acquisition of citizenship by blood (jus sanguinis). However, this right is interpreted differently by different countries and depends on a number of factors of which the most important seems to be the gender of the citizen-parent.
It may be a surprise to Americans and French but historically acquisition of citizenship by jus sanguinis was limited to children whose fathers were citizens. Women who married foreign men were stripped of their citizenship and disqualified from transmitting that citizenship to their children even if they remained on French or U.S. soil.
Jus Sangunis in France: A Long Road to Equality
The Civil Code of 1803 which instituted jus sanguinis in France was restricted to children of French fathers. The man was considered the head of the house and so citizenship, like the family name, followed the father's line, not the mother's. This led to a rather disagreeable situation: most people born of foreign fathers in France were not French citizens and so could not be drafted into the army. Given the events of late 19th century Europe, this was a terrible state of affairs from the point of view of the French State. This was rectified by a law passed in 1889 which allowed for double jus soli - a child born in France of a French-born non-citizen parent became a French citizen automatically.
Nevertheless, it was not until 1927 that the laws were changed to allow Frenchwomen to keep French citizenship if they married a foreigner and to pass their citizenship along to their children. Again, this was a question of state interest. Between 1914 and 1927, 120,000 Frenchwomen became foreigners because of marriage to foreign men. During that time only 60,000 foreign women became French due to marriage with French men. This meant a net loss of 60,000 citizens in a little over a decade.
Post World War II saw new restrictions limiting the right of Frenchwomen marrying foreigners but in 1973 a law was passed eliminating all discrimination against Frenchwomen. And that is where the situation stands today.
The United States: Not Quite There....
In the U.S. the situation was less clear but it appears that principle of "dependent nationality" was also enforced. In 1897, Secretary Sherman wrote “By our statute an alien wife of an American citizen shares his citizenship. By the usual rules of Continental private international law, a woman marrying an alien shares his status...”
In 1907 it was made official when Congress passed the Expatriation Act which clearly stated that a female U.S. citizen automatically lost her citizenship upon marriage to an alien.
Some relief was provided in the 1922 Cable Act. Loss of citizenship was no longer automatic but a woman still lost her United States citizenship if she married an alien ineligible for citizenship. In addition, it was assumed that she renounced her American citizenship if she lived in her husband's country for two years or if she lived abroad for five years. A woman who became a naturalized citizen of another state could not transmit her citizenship to her children. Given that naturalization was often automatic in the husband's country, the end result was that the woman lost her American citizenship and could not transmit American citizenship to her children. (If this were still true I would have lost my American citizenship years ago!)
A number of acts between the 1930's and the 1990's gradually eliminated the automatic loss of citizenship for women married to foreign citizens. American women acquired the right to transmit U.S. nationality to their children born abroad in 1934.
The law is still unclear about American women who marry foreign men and choose to become naturalized citizens of their husband's country. Since 1990 the State Department answers such queries with this note which says that being naturalized in a foreign country is grounds for losing citizenship if it is done with the specific intention of renouncing U.S. citizenship. So theoretically one can become a dual citizen as long as the intention is to keep U.S. citizenship and the U.S. State Department acts under the assumption that a U.S. citizen acquiring citizenship in another state wishes to keep his/her U.S. nationality. For those of us who are U.S. citizens contemplating naturalization in our countries of residence this is an awfully shaky post upon which to hang our hats. (May I state for the record here that I have absolutely no intention, now or in the future, of renouncing my U.S. citizenship?)
Interestingly enough, the transmission of U.S. citizenship by jus sanguinis is not gender-neutral and is unfavorable to American fathers of children born abroad. In 1790 American law was clear: children born outside the U.S. to American fathers were automatically U.S. citizens. Today, the situation is not so simple. In 2011 the American father of a child born out of wedlock must prove that the child is his and agree to support the child until age 18. In addition he must have resided in the U.S. for at least 5 years and two of those years of residency must be after age 14. The only requirement for an American woman in the same situation is that she must have lived continuously in the U.S. for one year at some point in her life.
I have no explanation for this. Contemplating the legal history of citizenship transmission by blood in both countries, I am struck by how often these law have been changed or re-interpreted depending on the times and, quite frankly, the requirements of the state. It does make you wonder what might happen in the years to come depending on which way the political winds blow. Transmission of citizenship by jus sanguinis is not a given - it is a hard won right which none of us should take for granted.
In writing the above essay, I have relied heavily on two very good books:
Citizenship Today: Global Perspectives and Practices edited by T. Alexander Aleinkoff and Douglas Klusmeyer (2001) and The Politics of Citizenship in Europe by Marc Morje Howard. For the latter I have written a review for Amazon which can be found here.