The 14th Amendment

Section 1, which contains the Citizenship Clause, of the 14th Amendment guarantees that right for all children born in the U.S.

 "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. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty or property, without due process of law, nor deny to any person within its jurisdiction the equal protection of the laws."

The 14th Amendment was passed by Congress in 1866 after the Civil War and during the period of Reconstruction. The amendment was ratified on July 9, 1868 by three-fourths of the states. By extending citizenship to those born in the U.S., the amendment nullified an 1857 Supreme Court decision (Dred Scott v. Sandford), which had held that those descended from slaves could not be citizens.

A biased Supreme Court could decide that the 14th amendment applies only to blacks, or it could find the 14th amendment unconstitutional. 

What is constitutional, is what the Supreme Court says is constitutional. The 14th amendment changed what the Supreme Court previously found constitutional, that blacks were not citizens. The Supreme Court can reverse their previous decision, just as they can reverse Roe/Wade, or any other law.

For those who fear a fascist like takeover of our government, it starts with getting the ruling court of the country to overturn accepted laws. That's how Hitler started and when he became Fuhrer he simply declared what the law was.

Can it happen in the United States? YES.

Trump cannot overturn the 14th amendment by a simple executive order, but with help from the Supreme Court that executive order can be found constitutional and become law.

"Only now at the end" do we understand the importance of a Supreme Court decision.