The correct perspective:
Giving citizenship to children born to illegal aliens was/is unconstitutional.
This is classic “Art of the Deal”. This is Trump’s starting point for negotiation. Wall funding incoming!
Well, not exactly.
The Fourteenth Amendment declares that SOME people who are born in the U.S. are citizens of the U.S. It would be unConstitutional to deny any such person that status.
The Fourteenth Amendment is silent regarding all other persons. However, the Constitution is not silent. Among the powers granted to Congress is the following: "To establish an uniform Rule of Naturalization".
This means that it is Congress' job to decide about the citizenship of people whose status is not dictated by the Constitution or common law.