Get laws changed to allow only legal people in public schools and the country would probably save 50 billion a year at a minimum.
Eliminate birthright citizenship to the anchor babies of illegal alien parents. Prosecute employers who employ illegal aliens. Deport illegals when detected and require them to take their minor children back to their country of citizenship. Those steps would kill the job magnet and the attraction to the welfare state. Many would self deport. Every illegal removed from the country represents an ongoing savings to the taxpayers.