Arizona Law?

Arizona is proposing a law to make it illegal to be in the state without legal immigration documents. WTF, isn't already against the law. I applaud Arizona, but just round them up and ship them home. Pick them up when they get their driver license, food stamps, lottery winnings, welfare checks, outside Home Depot and when they visit the emergency room. How hard would that be? Do that a little cost and save the state millions.