...The only problem is that the birthright citizenship issue has been settled for a long time...
True, but there are a variety of matters in which SCOTUS has ruled one way, in one era, then reversed itself, in another era, yes?
And, if that is the case, then SCOTUS can simpy RE-interpret the 14th to hold that it was intended to provide relief to former slaves, not to open a loophole for Anchor Babies.
...Congress has no power to take it away from birthright children ex post facto. ...
True.
We're stuck with the Anchor Babies already here.
But, moving forward, that can be a different story, given the right ruling by SCOTUS.
And, of course, we can also insist that any Anchor Babies already here, be accompanied by parent or legal guardian who is legally entitled to be upon US soil.
That should take a big damned bite out of the Anchor Baby presence - dashing the hopes of Illegals who sneak into the country and then pop out their Anchor Puppies because the dumb-ass, dim-witted, soft-hearted, soft-headed Gringos can't bring themselves to send them packing...