Citizenship in the United States is currently defined in the Bill of Rights under the 14th Amendment. Ratified in 1868 in the wake of the Civil War to ensure the citizenship of all free African Americans, it states: “All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the state wherein they reside.” The definition was put to the test in the late 1890s when the Supreme Court heard United States v. Wong Kim Ark. In this case, the Court found that people born on U.S. soil were considered citizens even if their parents were not.
But go back about a century to the 1780s, and the definition of U.S. citizenship seems less well defined. The Constitution and the Bill of Rights do not specifically define citizenship, but they do mention it. In Article I, citizenship is a requirement for holding legislative office. Article II states: “No Person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this Constitution” may be eligible for president. The Founders clearly had an idea of what citizenship meant but opted not to spell it out.
Right of the Soil
Federalists like Alexander Hamilton and anti-Federalists like Patrick Henry may not have agreed on much when crafting the Constitution, but they did share a common, practical understanding of English common law—a tradition the young nation inherited from Great Britain. Under common law, citizenship was determined using the principle of jus soli—a Latin term meaning “right of the soil” or birthright citizenship. In general, if one was born on British soil, then one was a British subject. The Founders carried this principle forward in their new government, and jus soli became the "law of the land" for American citizenship.
Right of the Blood
Another concept—jus sanguinis (“right of the blood”)—also came into play in defining who was a citizen in the new nation. Under this principle, citizenship was hereditary, passed down from fathers to their children. In March 1790, Congress passed “An act to establish an uniform Rule of Naturalization,” which established that children born to American men abroad or at sea were still considered “natural born citizens.” The status of their fathers would be conferred upon the children no matter where they were born. (Beginning with France in 1804, the nations of Europe began applying jus sanguinis standards to define citizenship, a continuing practice today).
The bulk of the 1790 act also spells out how new arrivals to America could become U.S. citizens. “That any Alien being a free white person, who shall have resided within . . . the United States for the term of two years, may be admitted to become a citizen.” They must also prove to possess “good character” and swear an oath of loyalty to the Constitution. Their children, regardless of birthplace, also became citizens when their fathers did. The act was amended in 1795 to extend the residence period to five years, which would remain the standard for most of the 19th century (in 1798, it spiked to 14 years but reverted back to five in 1802). (Explore U.S. immigration trends from the last 200 years.)
The Early Republic
Questions of citizenship arose often during the early Republic, usually in cases regarding people born around the time of the Revolution, but the courts supported the application of jus soli in these cases. (Learn more about 19th-century America's anxiety over immigration.) One of the earliest cases regarding birthright citizenship, Lynch v. Clarke, came out of New York in 1844 and found that a daughter born in New York state to Irish parents was considered a U.S. citizen, even though her parents returned to Ireland. Judge Lewis Sandford wrote:
“[B] the law of the United States, every person born within the dominions and allegiance of the United States, whatever were the situation of his parents, is a natural born citizen. . . . The term citizen, was used in the constitution as a word, the meaning of which was already established and well understood. The only standard which then existed . . . was the rule of the common law, and no different standard has been adopted since.”
In 1857 Justice Benjamin Roberts Curtis, dissenting in the Dredd Scott decision, argued that the Constitution’s use of the term “natural born citizen” in Article II “assumes that citizenship may be acquired by birth. Undoubtedly, this language of the Constitution was used in reference to that principle of public law, well understood in this country at the time of the adoption of the Constitution, which referred citizenship to the place of birth.” When writing the majority decision for United States v. Wong Kim Ark, Justice Horace Gray relied on the words of Curtis and other decisions before him to uphold the citizenship clause 14th Amendment.
The common law practice of jus soli is still a custom around the world today. Most countries in the Western Hemisphere—including the United States, Canada, Mexico, Brazil, Chile, and Argentina—still use it to grant citizenship while most of the world’s nations—such as the United Kingdom, Egypt, India, Russia, and Japan—rely on the jus sanguinis tradition and require at least one or both parents be citizens for a child to claim citizenship.