Immigration laws - How would you feel about this?

I was listening to a talk radio station yesterday and the interview was with Senator Alan Abel (D-Delaware). The topic came to immigration and the Arizona law. The senator said that the federal government should p a law that prohibits states from enacting any law(s) that impede, inhibit or restrict the page of immigrants and / or question the citizenship status of any person(s) within the US. This would trump the Arizona law and discourage any other state from ping similar laws.