This article by Nina Totenberg, a well known Supreme Court reporter, discusses next weeks SCOTUS hearing on a yet another emergency appeal from the Trump administration re: banning birthright citizen for migrants. The 14th amendment appears to be rather unambiguous saying:

"All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States." And courts have all said no matter the citizenship of the parents, all babies born in the US are US citizenship. But legal experts see something else in play.

The Trump administration's (the solicitor general) filing spends far more time on the power of lower court judges to issue nationwide injunctions, as in this case, than it does on the question of birthright citizenship. That may be because some of the Court's justices have often complained about such nationwide rulings, and rather than deal with the birthright citizenship question, where the administration faces an obvious uphill battle, it may think it has a better shot attacking nationwide injunctions, and getting more favorable lower court opinions in more friendly venues than say California District Courts. Indeed, many experts expect.a narrow victory for Trump on the nation wide ruling issue and not on the merits of birthright citizenship.

https://www.pbs.org/newshour/politics/supreme-court-sets-date-in-may-to-hear-arguments-on-trumps-birthright-citizenship-orde

Stay tuned.

There is an argument to be made in favor of the administration's interpretation of birthright citizenship. That said,, I struggle mightily to understand how that position is enacted through an EO. So even if their 'underdog' interpretation of the 14A is an eventual winner I don't think they get their win doing it this way.