I have a hunch that any kind of blow-up on immigration will virtually necessitate a Hispanic person on the 2016 ticket to neutralize the "racism" charges. Susanna Martinez is one such example that comes to mind, an example of someone who worked her way up and played by the rules. She has solid conservative bona fides, is fluent in Spanish, and is quite well-liked in NM, having cruised to an easy re-election.
Getting a good chunk of the Hispanic vote in 2016 is a great way to neutralise the solid black vote that the Dems always seem to get.
Walker/Martinez 2016 anyone?
In summary, if Obama does this the Republicans could come out smelling like a rose come 2016, with Walker's stellar accomplishments in Wisconsin and Martinez's popularity in New Mexico, thereby possibly picking off two blue states.
Cruz is another option (Cuban American), the anti-Obama whom just about all of us love. I just worry about running a senator at the top of the ticket.