For generations, the birth certificate has been the cornerstone of how Americans verify their citizenship. But that standard may soon be upended.

On Day 1 of his second term, President Trump signed an executive order attempting to rewrite the 14th Amendment of the U.S. Constitution and end birthright citizenship as we know it. The order said that children of immigrants would no longer receive U.S. citizenship unless one of their parents had already been naturalized or had a green card. This meant that the children of Dreamers and many other immigrants who have lived their whole lives in the United States would no longer be born citizens.

Within 24 hours, multiple lawsuits were filed to challenge the order. On Feb. 5, Judge Deborah L. Boardman of the U.S. District Court in Maryland issued a nationwide injunction stopping the federal government from putting this unconstitutional policy into effect. Since then, every court to consider this issue has ruled that Mr. Trump’s order should not go into effect.

There have been several news stories about the birthright citizenship case, and the Supreme Court will hear oral arguments in the case on Thursday. The majority of these stories have focused on technical legal questions: whether and under what circumstances lower courts should be able to issue nationwide temporary injunctions and stop a federal policy from going into effect nationwide while the case winds its way through the courts. But the focus on this legal question has obscured what is really at stake: the definition of U.S. citizenship and what it means to be an American.

If the Trump administration prevails in its crusade to overturn birthright citizenship, it will result in a population of newborns without legal status.

Since Reconstruction, any child born in the United States has been able to access citizenship, regardless of their parents nationality or race.