The Citizenship Clause is the first sentence of Section 1 in the Fourteenth Amendment to the United States Constitution, which states that "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." This clause represented Congress's reversal of a portion of the Dred Scott v. Sandford decision which had declared that African Americans were not and could not become citizens of the United States or enjoy any of the privileges and immunities of citizenship.
The Civil Rights Act of 1866 had already granted U.S. citizenship to all persons born in the United States "not subject to any foreign power". The 39th Congress proposed the principle underlying the Citizenship Clause due to concerns expressed about the constitutionality of the Civil Rights Act during floor debates in Congress. The framers of the Fourteenth Amendment sought to entrench the principle in the Constitution in order to prevent its being struck down by the Supreme Court or repealed by a future Congress.
Amendment XIV, Section 1, Clause 1:
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 Citizenship Clause mentions naturalization, which is the process by which immigrants are granted citizenship. Congress has this power by virtue of Article I, Section 8, Clause 4 of the Constitution, known as the Naturalization Clause.
The text of the Citizenship Clause was first offered in the Senate as an amendment to Section 1 of the joint resolution as passed by the House.
There are varying interpretations of the original intent of Congress, based on statements made during the congressional debate over the amendment. While the Citizenship Clause was intended to define as citizens exactly those so defined in the Civil Rights Act, which had been debated and passed in the same session of Congress only several months earlier, the clause's author, Senator Jacob M. Howard of Michigan, phrased it a little differently. In particular, the two exceptions to citizenship by birth for everyone born in the United States mentioned in the Act, namely, that they had to be "not subject to any foreign power" and not "Indians not taxed", were combined into a single qualification, that they be "subject to the jurisdiction" of the United States, and while Howard and others, such as Senate Judiciary Committee Chairman Lyman Trumbull of Illinois, the author of the Civil Rights Act, believed that the formulations were equivalent, others, such as Senator James R. Doolittle from Wisconsin, disagreed, and pushed for an alternative wording.