[Latin: law relating to blood]
The principle that the nationality of children is the same as that of their parents, irrespective of their place of birth. This contrasts with * jus soli, whereby nationality is dependent on place of birth. In states in which the jus sanguinis principle applies (i.e. France and Germany), a conflict of jurisdiction may arise when a child is born of parents who are citizens of another state. For example, a child born in the United States of French parents is an American citizen jure soli, but a French citizen jure sanguinis. His effective citizenship will depend upon the jurisdiction within which he happens to be in; in the United States he is a US citizen; in France, a Frenchman; in any other country he is both.
Conflicts resulting from the simultaneous presence of these contrasting claims of allegiance are generally settled between states by deferring jus sanguinis to jus soli when the state asserting its primary claim of allegiance has de facto jurisdiction of the individual in question. Most jurisdictions (including the United Kingdom and the United States) now adopt within their nationality law a combination of jus soli and jus sanguinis.