Honestly my real fear is ICE agents at polling places on Election Day harassing would-be voters with citizenship checks and aggressive behavior, slowing things down and maybe causing some people to leave.

Regarding voter data though, if it becomes known that registering to vote as a minority will get you extra scrutiny from ICE, and perhaps a visit to your home, that would probably cause some citizens avoid voting altogether, especially if they are associated with people who are not her legally.

Either way, the federal government really has no right to that data or legitimate use for it, so hopefully they don't manage to get their hands on it.