Sent them all back. Make California's Prop. 187 into federal law.
Denial of all social benefits is the first step. That will slow down the magnet effect which pulls illegals in to the United States. Jail time in the slammer for employers WILLINGLY employing and disregarding federal laws is also a step that can be taken to retard the "market pull." Finally, a way around of rendering unacceptable, on the state level, the various "Matricula Consular" ID cards issued by various nations, is also a step in the right way.
Take away so-called "rights" for these individuals, which they are not entitled to in the first place.
I am entitled to NOTHING in Japan, for example, if I sneak in and violate the Nyukoku Kanri Horitsu law governing legal crossing of international borders. Why does our system run on the assumption of "non-existent rights"?