President Donald Trump says he wants to sign an executive order ending "birthright citizenship" for babies of non-citizens born on U.S. soil.

Most citizens are taught early in their education that birthright citizenship is an immutable, undisputed right, explicitly granted by the Constitution. But, it turns out, birthright citizenship may not be a constitutional right.

The Citizenship Clause of the 14th Amendment — enacted in 1868 — reads "(a)ll 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."

If the clause simply omitted "and subject to the jurisdiction thereof" then there would likely be no debate, and birthright citizenship would be unassailable absent a constitutional amendment. But the "subject to the jurisdiction" language has created a lot of debate over the years.

To some scholars, birthright citizenship has been the result of an accidental interpretation of the Constitution, federal law and Supreme Court precedent — an error that they believe can be corrected without Constitutional amendment.

Shortly after the passage of the 14th Amendment, the Supreme Court in 1872 had an opportunity to interpret it in the "Slaughterhouse Cases," observing that the amendment's "main purpose was to establish the citizenship of" African-Americans. It also concluded that "subject to the jurisdiction thereof" was meant to exclude the children of "ministers, consuls, and citizens or subjects of foreign states born within the United States."

The argument goes: If these categories of people were not "subject to the jurisdiction" then it follows that babies born of illegal immigrants have even less claim to citizenship.

But then, in 1898, the Supreme Court decided U.S. v. Wong Kim Ark, holding that "a child born in the United States, of parents of Chinese descent, who, at the time of his birth, were subjects of the emperor of China, but have a permanent domicile and residence in the United States" was entitled to citizenship based on his birth on American soil.

This case, together with the clear meaning of every other part of the Citizenship Clause — except for that tricky "subject to the jurisdiction thereof" part — form the bulk of the strongest arguments for birthright citizenship: To supporters, it's in the 14th Amendment, and the Supreme Court appears to have squarely decided the issue.

But maybe it didn't. The Wong Kim Ark case did not actually decide whether children of illegal immigrants are entitled to birthright citizenship — only children of immigrant parents with "permanent domicile" in the United States.

Some scholars go further and argue that the Wong Kim Ark decision is completely erroneous, and based on a mistaken interpretation of the 14th Amendment — a mistake that has caused a major constitutional misunderstanding that persists to this day.

Those against birthright citizenship ultimately conclude that while the 14th Amendment Citizenship Clause has been misapplied, it was always intended to grant citizenship only to people who are born here and whose parents are not foreign subjects.

To them, "subject to the jurisdiction" clause is not just some meaningless phrase, because there is a presumption that laws and the Constitution do not contain surplus or meaningless words. For the same reason that children of diplomats and invading armies would not be citizens, children of illegal immigrants should not be either. All of these children are — by this interpretation — not "subject to the jurisdiction" of the United States.

Those who support birthright citizenship have a more straightforward argument. Whatever "subject to the jurisdiction" ultimately means, it doesn't change the rest of the language of the Citizenship Clause. If that vexing phrase has any limiting meaning, it just refers to the jurisdiction of the laws of the United States —just as someone who commits crimes in interstate commerce is "subject to the jurisdiction" of the U.S. government.

Whichever side is right, there's a compelling historical — if not legal — argument for not amending the Constitution to remove birthright citizenship. The Constitution has been amended to expand rights and increase protections. It is rarely amended to remove existing rights.

Arguably, the one time that has occurred in our history was the 18th Amendment, which imposed a federal criminal prohibition on alcohol. By any measure, that was ultimately a spectacularly unsuccessful amendment.

Danny Cevallos is an MSNBC legal analyst. Follow @CevallosLaw on Twitter.