If they are fingerprinted and issued some form of SS ID, then employers can collect/pay employment taxes. This means that guest workers can then collect benefits at some later point in their home country.
The real KEY is regularization: once there is some official program, guys like Gov Arnold can push through laws that allow local agencies to sic the cops on non-conforming parties.
The libs will be without a platform to cry 'racism' because the entire issue will have been converted to an administrative process.
Let's try to look at this like intelligent conservatives. Snerffy's summed it up masterfully. This is what it's all about.