It is time to build an electrified fence with entry/exit points with armed guards. ANYONE attempting to come or go without passing through legally, will be arrested and jailed. Those from other countries will be sent home, and a bill sent to their country of origin. Let them sort it out, or execute them for all I care. Make proof of citizenship for legitimate employment the standard here, levy massive fines to employers that hire illegals, and shut off the social service pipeline for them. There, I have fixed the problem, all it took was a willingness to enforce the law.
Gov't never has a problem enforcing our laws against citizens.