How politically things are likely to work is a different question from what is Constitutionally required.
EDIT: also,
> The feds clearly won't even impose "are you here legally in the first place" restrictions. Bush and Obama have made that perfectly clear.
George W. Bush's administration engaged in some of the most extreme uses of every federal power available (and more)over immigrants since WWII in the wake of 9/11.
They may not have used that power where you want them to, but that's a different issue.
How politically things are likely to work is a different question from what is Constitutionally required.
EDIT: also,
> The feds clearly won't even impose "are you here legally in the first place" restrictions. Bush and Obama have made that perfectly clear.
George W. Bush's administration engaged in some of the most extreme uses of every federal power available (and more)over immigrants since WWII in the wake of 9/11.
They may not have used that power where you want them to, but that's a different issue.