Rather than shrink the size of the unauthorized population in the United States, repeal would likely expand it — and expand it substantially. A second worrying finding is that repeal would set in motion a sizeable, self-perpetuating class of unauthorized immigrants for generations. This perpetuation of hereditary disadvantage based on the legal status of one’s ancestors would be unprecedented in US immigration law.
Supporters of the legislation have in mind that (a) people would no longer migrate to the United States if they knew that they could no longer produce an "anchor baby" and (b) that a family would be easier to deport if all members of the family are unauthorized immigrants. The MPI study suggests that, in fact, the unanticipated consequences of this proposed change would be radically different than expected by its supporters.