A point that hasn't been brought up here is how enforcement on corporations/businesses will go.
When you cut off that cheap labor source business have 2 options:
1) Downsize
2) Move jobs overseas
Neither one of these options is going to promote economic growth.
Those jobs going to American poor will still require these companies to pay higher wages, pay benefits, and pay taxes on money they used to pay under the table. You also take away the taxes that illegals that were actually able to obtain a ITIN number.
The U.S. essentially has to be prepared to go into a recession in order to start enforcement across the board.
For those that don't remember, the last time the government tried to take away a cheap labor source from corporations half of the country broke off and they fought for 4 years