U.S. does not exercise passport control on exit from the country, so the individual attempting to depart from the U.S. only needs to have valid documents granting the right to entry into the country of destination. Travel of U.S. citizens and nationals around the United States and across its international borders is generally controlled by means other than passports, such as the No Fly List. Requirements Citizens United States passports are issuable only to persons who owe permanent allegiance to the United States – i.e., citizens and non-citizen nationals of the United States. Under the 14th amendment to the US Constitution, "All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States ..." Under this provision, "United States" means the 50 states and the District of Columbia only, but also technically includes the uninhabited Palmyra Atoll, an incorporated territory due to the Insular Cases. By acts of Congress, every person born in Puerto Rico, the U.S. Virgin Islands, Guam, and the Northern Mariana Islands is a United States citizen by birth. Also, every person born in the former Panama Canal Zone whose father or mother (or both) was a citizen is a United States citizen by birth. Other acts of Congress provide for acquisition of citizenship by persons born abroad. Non-citizen nationals Every citizen is a national of the United States, but not every national is a citizen. The only current example of non-citizen US nationals are those born in American Samoa (including Swains Island). Unlike the other current US territories, people born in American Samoa are not automatically granted US citizenship by birth as the territory is not incorporated and an act of Congress granting it, similar to other US territories, has not yet been passed for American Samoa. The other historical groups of non-citizen US nationals include those of former US territories and during periods of time before the acts of Congress granting citizenship to those born in current territories. Passport in lieu of certificate of non-citizenship nationality Few requests for certificates of non-citizenship nationality are made to the Department of State, which are issuable by the department. Production of a limited number of certificates would be costly, which if produced would have to meet stringent security standards. Due to this, the Department of State chooses not to issue such certificates; instead, passports are issued to non-citizen nationals.