As it is wont to every few years, dual citizenship has become a contentious issue in contemporary politics. In the wake of the November 2015 attacks in Paris, French President François Hollande is pressing for a constitutional amendment that would allow convicted terrorists with dual nationality to be stripped of their French citizenship. Political elites on the French left have attacked the proposal as violating principles of equality, as it does not apply to citizens of only France; the move, they argue, would signify that dual nationals are somehow less French and that their French identity is more expendable than those who don’t have another citizenship. In December the U.S. Congress barred dual nationals of Iran, Syria, Iraq and Sudan from visa exemptions that they would otherwise enjoy as citizens of European Union nations and certain other countries. The measure — which a group of senators is now proposing to alter — also restricts the visa-free movement of individuals who have recently traveled to these countries, on the theory that it would prevent potential jihadists from re-entering the …