order to enjoy privileges and immunities in any other state. Right to travel The Privileges and Immunities Clause says that a citizen of one state is entitled to the privileges in another state, from which a right to travel to that other state may be inferred. Under this clause such an internal passport which is in use in a small minority of countries, would be unconstitutional. Indeed, in the 1982 case of Zobel v Williams, a majority of the U.S. Supreme Court agreed that the Privileges and Immunities Clause plausibly includes a right of interstate travel. In that case, Justice Sandra Day O'Connor explained: Article IV's Privileges and Immunities Clause has enjoyed a long association with the rights to travel and migrate interstate. The Clause derives from Art. IV of the Articles of Confederation. The latter expressly recognized a right of "free ingress and regress to and from any other State," in addition to guaranteeing "the free inhabitants of each of these states . . . [the] privileges and immunities of free citizens in the several States." While the Framers of our Constitution omitted the reference to "free ingress and regress," they retained the general guaranty of "privileges and immunities." Charles Pinckney, who drafted the current version of Art. IV, told the Convention that this Article was "formed exactly upon the principles of the 4th article of the present Confederation." Commentators, therefore, have assumed that the Framers omitted the express guaranty merely because it was redundant, not because they wished to excise the right from the Constitution. Early opinions by the Justices of this Court also traced a right to travel or migrate interstate to Art. IV's Privileges and Immunities Clause....Similarly, in Paul v. Virginia, the Court found that one of the "undoubt[ed]" effects of the Clause was to give "the citizens of each State . . . the right of free ingress into other States, and egress from them.... Despite scholarly and judicial opinions acknowledging that the Privileges and Immunities Clause may include a right to travel, the issue is not without controversy. Miscellaneous Unlike the Dormant Commerce Clause, there is no market participant exception to the Privileges and Immunities Clause. That means that even when a state is acting as a producer or supplier for a marketable good or service, the Privileges and Immunities Clause may prevent it from discriminating against non-residents. Puerto Ricans were granted U.S. citizenship