What's so wrong with that? For one --- sending them back in nice comfortable buses is nothing when you look at the way Mexico sent them to us. And --- it would be the very best thing that could happen to Mexico --- imagine one-fifth of it's citizens suddenly coming back home -- after being exposed to the way Americans live a nice middle class lifestyle --- they're going to demand the same thing there. Millions of Mexicans who learned to drive a tractor, use a telephone, drive a car??? That could be an unstoppable revolution --- toward modernity.
Mexico didn't send them FITZ. They fled Mexico.
Because it is impossible to be done, logistically, money wise, and from human point of view. If you are not willing to pick up the phone and inform the INS about the illegal immigrant bus boy who cleans the table for you in restaurant, then STFU and do not expect the President of the United States to issue an order to deport 15 million illegal immigrants.