Why does this principle carry such weight? Because jus soli is the anti-caste rule. Most of the world assigns citizenship by blood, jus sanguinis, meaning your membership in the nation is inherited, and so is your exclusion. Birthright citizenship refuses that. It means no child begins life as a subject rather than a citizen; no hereditary underclass can form, passing non-belonging from parent to child forever. Every baby born here starts equal, whatever their parents did or didn’t do, wherever they came from, however they arrived. It is the one American promise made at the moment of birth, before anything can be earned or ruined.

The alternative is not hypothetical. Strip it away, and you create generations born on American soil, educated in American schools, speaking American English—and legally foreign in the only country they have ever known. And the people this rule has made citizens are not abstractions: they include Wong Kim Ark’s descendants, the children of every immigration wave, and, by most accounts, a former vice president, born in 1964 to two students on visas, who under the order’s terms would not have qualified.

There is one more historical fact worth the discomfort. The people with the oldest claim to this land were among the last to receive its citizenship: the Supreme Court denied birthright citizenship to Native Americans in 1884, and Congress did not extend it to them until 1924. If being born on this land does not make one American, the logic runs in an awkward direction. The only people it unambiguously favors are the ones who were here first, and if we’re reopening that question, the land itself would presumably be owed back to them. Those who would narrow the right of soil should be careful how much history they invite into the room.