The government will do it the same way Obama, Pelosi and Reid will fine and imprison 15 million Americans who will not buy Health Insurance... Proving once again government always finds away to do something if they really want to....
Which raises the question: Does the government want to get rid of the 20 million illegals? It seems clear to me a majority of the government want them to stay. I'm not even sure a majority of Republicans want them to leave. It's easy to say you want them to. Let's see them do it. The efforts of the GOP==nevermind the DEMs---has been running in the other direction for quite some time now.
And it seems to me that the monied interests that line the pockets of our politicians are in favor of having them stay as well, and why not? Cheap labor! So how to get them out? That's the question.