The argument against birthright citizenship certainly has a long history, as can be seen in these legal opinions released within decades of the 14th Amendment’s enactment. But as I said at the outset, I don’t quite find it convincing, given the more direct evidence from the text and more immediate historical context — though it must be conceded that we have no idea what the framers of the 14th Amendment would have thought about illegal immigrants in particular, because illegal immigrants simply didn’t exist back then.
To defend an executive order before the Supreme Court, however, the Trump administration would need to convince all five originalist judges that “subject to the jurisdiction” must be read in a way that’s somewhat quirky to modern ears, relies on a highly specific reading of the historical evidence, and overturns more than a century’s worth of standard practice. That’s a longshot.
Birthright citizenship is a nutty policy. But if I had to bet, I’d say it’s one we’re stuck with.