I wonder if they have any idea the monster they've created. As reported, it seems as if the trumpies want to withdraw it and declare that it never existed as it's seen to by many, and not simply to end it as of a certain cutoff date. If that is the case, regression is automatic. If you are no longer a citizen, your children are no longer citizens. Their children are no longer citizens. Essentially, any person of any generation who cannot prove documented immigration of their most distant ancestors is open to deportation, even if they and their parents and grandparents were voters with passports.
I know that's extreme and silly, but we are in an age of extreme silliness, and it is topped off the big rotting fruit of stupidity.
edit to add, stupid as this seems, I realize it's even stupider because Trump has said he would apply the removal of birthright citizens to the children of WOMEN who are in the country illegally, which means they would be denied citizenship even if their fathers are citizens, and would, one presumes have their citizenship revoked if at some point the presumed legal status of their mothers is revoked. Since the administration has already managed to subvert the constitutional bar against ex post facto laws by retroactively de-legalizing formerly legal immigrants, including those with green cards, this is no joke. Though my children's mother is now a citizen, she was a permanent resident alien when all were born over 40 years ago. In theory, if she had not become a citizen, and decided at some point later, say, to protest against the Israeli killing of Palestinian civilians, they could all be subject to instant deportation. Silly, of course...until it is not.