“After all, if they have a mortgage and kids in the local public school, it would be difficult to uproot all that.”
It goes to the point of enforcing the laws. We have ways that a person becomes Naturalized. If you can’t follow them, you can’t be a citizen. You gotta go. Difficult or not.
All we need is people with the will to actually enforce the laws, whether that will comes from within or from pressure from others. Here's hoping it happens.