When the Constitution of the United States was made, a “citizenship of the United States” was recognized but nowhere defined, and it was nearly a century before it found specific statutory expression in the Civil Rights Act and the Fourteenth Amendment. Meanwhile, not only the courts, but the Executive, invariably recognized the validity of the Common Law Rule, and the Wong Kim Ark decision of 1897 merely restated it once for all.[20] CONCERNING AMERICANS BORN ABROAD There are certain elaborations and modifications of the two great principles mentioned above, serving both to confirm and circumscribe them. Children born abroad of American citizens in the foreign service of the United States government are citizens of the United States, and like citizenship comes by birth to children “born out of the limits and jurisdiction, whose fathers were or may be at the time of their birth citizens thereof.”[21] But the father must have been a citizen at the time of the birth of the child, and must have resided actually in the United States; that is, it will not do for him merely to have acquired citizenship abroad by the fact of the citizenship of his father without ever having resided in this country. If the father loses his citizenship after the birth of the child, it has been held that such child upon attaining his majority may revive his right to citizenship by establishing residence here. And by virtue of legislation enacted in 1907, these foreign-born children of American parentage are required, upon reaching the age of eighteen, to register their intention to become residents, and to remain citizens, of the United States, and upon attaining majority to take the Oath of Allegiance to the United States. The Department of State has been very liberal in interpreting this provision, allowing the declaration of intention to be made at any time after the person concerned has reached the age of eighteen, and before he has taken the oath, which may be at any reasonable time after his majority. The main question raised is that of good faith. Arises here the principle of “election of nationality”; many countries accord to a person thus in danger of what might be called “dual nationality” the right to choose. This is the case in France, Spain, Belgium, Greece, Italy, Portugal, Mexico, Chile, and Costa Rica. In Portugal, Italy, and France, failure to exercise this choice operates as a choice of citizenship there; in Spain, on the other hand, silence is construed as a choice of the foreign nationality. This is the purport of the American practice.[22] CHILDREN BORN AT SEA