This whole issue boils down to economics...illegals sneak into the US, get on the government welfare, steal jobs from americans, congest our streets, grocery stores, and DO NOT PAY TAXES. Any moron can figure out that if they get govt handouts, do not pay income tax, and then send the cash out of the country, sure the states are in the hole.
It will take years to straighten out this problem through the courts. Here is a solution many americans might find uneasy, but I assure you will work.
Every citizen who is here LEGALLY, has identification. Make it a law that EVERY financial transaction requires swiping a US recognized ID card that only proves legality to be here. THis includes all transactions, cash or otherwise. I, as a taxpaying american, would be happy to show my ID to purchase ANYTHING. Illegals are economically killing this country, and by the time the courts resolve the issue, thousands of more babies are born, and the economic situation gets worse.
Illegals are cutting the US off at the knees, and this approach will cut the illegals off the same way. If they can't purchase ANYTHING, they will be forced to go back where they came from.