The United States Supreme Court is hearing oral arguments on what may be the most consequential constitutional case of the decade: whether the Trump administration can restrict or eliminate birthright citizenship, the principle that anyone born on American soil is automatically an American citizen. It is a right guaranteed by the 14th Amendment, ratified in 1868 -- over 150 years of settled law. And Donald Trump wants to tear it up.

If this succeeds, no constitutional right in America is safe. None.

The language is not ambiguous. Section 1 of the 14th Amendment states: "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." It was written in the aftermath of the Civil War to guarantee citizenship to formerly enslaved people and their descendants -- to ensure that no government could ever again define an entire class of people as non-citizens based on their origin.

For more than a century and a half, this clause has been interpreted exactly as it reads. Born here, citizen here. The Supreme Court affirmed this in United States v. Wong Kim Ark in 1898, ruling that a child born in San Francisco to Chinese immigrant parents was a US citizen by birth. The precedent is rock solid.

The Trump administration's argument hinges on a creative -- critics would say absurd -- reinterpretation of the phrase "subject to the jurisdiction thereof." The administration claims this phrase was meant to exclude children of undocumented immigrants and birth tourists, people who enter the US specifically to give birth on American soil. The legal theory is that such individuals are not truly "subject to the jurisdiction" of the United States in the way the framers intended.

Constitutional scholars across the political spectrum have called this argument legally unfounded. "Subject to the jurisdiction" has always meant subject to American law -- which undocumented immigrants unquestionably are. They can be arrested, charged, tried, and deported under US law. They pay sales taxes. They are bound by every statute on the books. The idea that they are somehow outside US jurisdiction is fiction.

The birth tourism argument is a smokescreen. Birth tourism is a marginal phenomenon -- a few thousand cases per year in a country of 330 million. You do not take a constitutional amendment to the Supreme Court over a few thousand cases. You do it to establish a principle: that the government can decide who is and is not a citizen at birth, based on the immigration status of the parents.

This is about Latino immigrants. It is about the children of undocumented workers who pick American crops, clean American homes, build American buildings, and pay into a Social Security system they will never draw from. It is about creating a permanent underclass of people born in America who are not American -- a class defined by the color of their skin and the accent of their parents.

Outside the Supreme Court, thousands of protesters gathered, holding signs reading "Born Here, American Here" and "The 14th Amendment Is Not Negotiable." Counter-protesters, smaller in number, carried signs supporting the administration's position. The scene was tense. Police lined the steps.

The implications extend far beyond immigration. The 14th Amendment is the foundation of virtually every civil rights protection in American law. Equal protection, due process, the incorporation of the Bill of Rights against state governments -- all of it flows through the 14th Amendment. If the court rules that "subject to the jurisdiction thereof" can be reinterpreted to exclude a class of people, it opens the door to reinterpretation of every other clause.

What stops a future administration from arguing that certain naturalized citizens are not "really" citizens? What stops a state from claiming that residents who moved from another state are not "subject to the jurisdiction" for purposes of voting rights? The 14th Amendment is either a bedrock guarantee or it is not. There is no middle ground.

Legal observers expect the court's conservative majority to be skeptical of the administration's broadest claims but potentially sympathetic to narrower arguments about birth tourism. A narrow ruling could still do enormous damage by creating a crack in the wall of birthright citizenship -- a crack that future administrations will work to widen.

For a country that lectures the world about constitutional governance and the rule of law, America is remarkably willing to set fire to its own constitution when the politics demand it. The 14th Amendment was written to correct the original sin of American slavery. Gutting it to target immigrants would be a betrayal not just of the law, but of the nation's stated ideals. The world is watching to see if those ideals mean anything at all.