The latest and most overt way in which Donald Trump’s controversial candidacy has affected the Republican presidential primaries and our political conversations has been the reemergence of heated debate over birthright citizenship (better known through the concept of “anchor babies”). Virtually every GOP candidate has followed Trump’s lead and denounced this legal and Constitutional concept. This is a stunning reverse in a longstanding, evolving, contested debate over citizenship and naturalization in America.

While the Constitution is silent on the issue of immigration, it does grant Congress the power to “establish a uniform Rule of Naturalization,” and congressmen used that power soon after ratification. The 1790 Naturalization Act provided the means by which “any alien, being a free white person, may be admitted to become a citizen of the United States.” It also extended citizenship, once achieved, to children under 21 years of age, regardless of their birthplace. But in the same section the Act noted that “the right of citizenship shall not descend to persons, whose fathers have never been resident of the United States,” leaving open what such circumstances might look like but in any case establishing a complicated relationship between place, identity, and citizenship.

A number of other federal laws passed over the next decade amplified these complexities. The 1795 Naturalization Act repealed the prior act and added a number of new provisions, including the need for citizens to “renounce their allegiance to their previous state/sovereignty by name” and for an individual to “behave as a man of good moral character.” Those requirements foreshadowed the controversial 1798 package known as the Alien and Sedition Acts, which included three laws focused on immigration and citizenship. The Naturalization Act extended the period of pre-naturalization residency in the United States to 14 years. And the Alien Enemies and Alien Friends Acts, which were eventually repealed, allowed for deportation and imprisonment of non-naturalized residents from “hostile nations”; under the Alien Friends Act, even if such “aliens” were allowed to remain in the country they could never be naturalized as citizens.

This evolving set of definitions and laws also reflects just how much debates over citizenship have always been tied to both foreign policy conflicts and domestic politics. On the one hand, the Alien and Sedition Acts were partly inspired by a nearly decade-long undeclared war with France, which made many Americans fear French immigrants and French influences, such as those embodied by the 1793-1794 Citizen Genêt affair, in which the French minister to the U.S. allegedly worked to undermine U.S. foreign policy and gain popular support for France in a war with Great Britain. At the same time, the Acts reflected domestic politics. In part, they stemmed from Federalist fears of an emerging Jeffersonian voting bloc, a bloc that was comprised of Irish immigrants among other constituencies. To limit the quantity and power of such Jeffersonian voters, Federalists manipulated the citizenship laws.

Yet despite these factors and the legal changes they produced, the fundamental link between racial identity (“free white person”) and citizenship remained unchanged, and thus so did the limitation on which children were eligible for American citizenship. Over the next half-century, those links were gradually challenged. Certain states, for example, allowed Chinese residents to become citizens if they met the other naturalization requirements. Yet these advances themselves were contested and often overturned, as in the case of Section 14 of the 1882 Chinese Exclusion Act, which made it impossible under national law for Chinese Americans to become citizens.

While these laws and definitions affected every American community, they were particularly oppressive to African Americans. Members of this community were defined as outside American citizenship from the outset by that 1790 phrase “free white persons.” They were afforded partial voting and property rights in certain northern states over the next decades, but were denied the chance for full legal naturalization. Legal naturalization had benefits both practical – such as the ability to travel and eligibility for government jobs – and symbolic. And African Americans were overtly excluded from citizenship by the 1857 Dred Scott decision, which denied not just slaves (present or former) but also the descendants of slaves “the rights and privileges of a citizen” for all time.

The 14th Amendment to the Constitution, ratified in 1868, potently reversed all these histories. That is, by granting citizenship to “all persons born or naturalized in the United States,” with no reference to race, place, or any other limiting factors, the amendment did more than just give African Americans and their descendants the chance for citizenship. It also explicitly linked birth to citizenship for the first time, enshrining in our highest legal document the reality that to be born in the United States means a full membership in our political and social fabric. Our histories of naturalization have long been tied to conflicts and controversies and might well remain so, as illustrated by the 14th Amendment’s categorization of Native Americans as “wards” rather than citizens and thus as excluded from its protections, a wrong not righted until 1924. We cannot forget that historical exclusion, of course, but the 14th Amendment made clear, and wrote into the Constitution, an important ideal: that American children, of all communities, must be kept separate from political debates and social conflicts.

Those who seek to repeal the 14th Amendment or otherwise eliminate birthright citizenship are doing more than challenging the Constitution. They are seeking to undermine and reverse one of our most significant legal and social advances, and one of the most vital ways in which our national community has been extended since our founding.