Judicial Activism?

A federal judge has blocked enforcement of an ordinance in Farmers Branch, Texas, that would have required landlords to verify that a person is in the country legally before renting that person an apartment or house.  The federal judge stated the ordinance is an infringement on the federal government's constitutional authority to regulate immigration.

 

I imagine this case will be appealed, perhaps up to the U.S. Supreme Court. I'm wondering about the implications of the ruling if it withstands the scrutiny of appeal.

 

If only the federal government can regulate immigration, and the benefits that accrue to immigrants, I would like a judge to explain why this court's decision does not affect a state's requirement that a person be a U.S. citizen before being permitted to register and vote.