Spain offers a right-of-return citizenship as well. Probably other countries, too.

Would we need to hold a treaty in place with all RoR countries for if someone became a politician to revoke that right? They could always get into office then ignore it after the fact. How could it be enforced after the damage was already done? What if instead of offering citizenship they offered bribes and cash as has been being done?

No idea what the solution could be, but it seems like a tricky situation.