Sounds like a dry run to ban birthright citizenship outright if there is not a big uproar about this. They also want to make sure that if a service member gets the natives pregnant and he doesn't want to deal with the child, he can just come back to the US and not file any papers and the mother can't get child support or get any kind of benefits. In other words, they didn't like what happened with all those half Korean and half Vietnamese kids who became citizens after those wars.