Vox reports that the concept of birthright citizenship in the United States is under attack again. But in some quarters, it has been under attack since it was codified in the Constitution with the Fourteenth Amendment in 1868.

Birthright citizenship, or jus soli (“right of soil”), means that a person is a citizen of the nation they are born in even if their parents are not. In the United States, the first sentence of the first section of the Fourteenth Amendment is known as the Citizenship Clause. It seems straightforward enough: “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 was written after both the Supreme Court’s infamous Dred Scott decision of 1857—which found that “persons of African descent” were not and could not be citizens, even if they were free—and the Emancipation Proclamation issued in 1862. In one broad Constitutional sweep, the Fourteenth Amendment defined those born in the United States, including ex-slaves and children of immigrants, as citizens.

The first challengers to the Fourteenth Amendment were the defeated states of the Confederacy. The white supremacy underlying the slave economy did not consider persons of African descent citizens, or even fully human. Virginia, North Carolina, South Carolina, Georgia, and Louisiana all rejected the Amendment between 1866 and 1867. However, to gain entry back into the Union, these states were essentially forced to ratify the amendment. Most came back and approved the amendment by 1868, meeting the 3/4ths-of-the-states requirement for amendments to be ratified. Maryland, which remained a border state during the Civil War, held out on ratifying the amendment until 1959.

Antipathy to birthright citizenship simmered on the nativist fringes of politics. Flash-forward to the mid-1990s, when several Republican members of Congress rallied around Republican California Governor Pete Wilson and proposed to amend the constitution to prevent American-born children of undocumented aliens from receiving citizenship as a birthright. This unsigned Note in the Harvard Law Review argued strongly against such an amendment because if would have created conditions that conflicted with one of the bedrock “foundations upon which American society is built—the principle of equality before the law.” This principal “demands that certain children not be treated differently from other children solely on account of the actions or status of their parents.” The amendment went nowhere, although the sentiment behind it obviously remained.

In 2011, Republican House of Representative members again raised the issue. The American Bar Association’s House of Delegates resolved that year to reject such efforts to change the Fourteenth Amendment’s Citizenship Clause: “Efforts to restrict the right of citizenship under the citizenship clause of the 14th Amendment… are a significant threat to the civil rights of Latinas and Latinos in the United States, including their right to participate fully in the United States legal system.”

The Fourteenth Amendment has survived its various challengers thus far, and turns one hundred and fifty this year.