Why Trump cannot end birthright citizenship:
Birthright citizenship is in a constitutional amendment (14th Am.)
To change that amendment, one needs to look at Article 5 of the Constitution. It states:
The Congress, whenever two thirds of both houses shall deem it necessary, shall propose amendments to this Constitution, or, on the application of the legislatures of two thirds of the several states, shall call a convention for proposing amendments, which, in either case, shall be valid to all intents and purposes, as part of this Constitution, when ratified by the legislatures of three fourths of the several states, or by conventions in three fourths thereof, as the one or the other mode of ratification may be proposed by the Congress; provided that no amendment which may be made prior to the year one thousand eight hundred and eight shall in any manner affect the first and fourth clauses in the ninth section of the first article; and that no state, without its consent, shall be deprived of its equal suffrage in the Senate.
So either Congress can do it or the states can do it by calling for a convention.
If Trump does this, I do not understand how anyone can call themselves a conservative and support him because all he does is sign pieces of paper that cause chaos and confusion and get held up in litigation for years wasting valuable government resources.