One illegal at a time.
Do that enough times, and the rest will get the message.
It's happening as we speak in Arizona...where I'm from.
No nonsense laws were passed. So they kicked, they screamed, they huffed, they puffed....just like my kid....and then....they had to leave.
Because even the courts couldn't give them a pass. The citizens of Arizona held fast, and didn't give in to the Leftist hustle: lawsuits, name calling, guilt tripping, finger pointing, race baiting, threats of violence, actual violence, whining, crying, whatever they can dream up....nope, they finally ran into a wall: real Americans who said, "these are our laws. obey them now".
Read post 28 and 29. They add things I would have added too.
It's a matter of will. And let the Left in this country scream. The only thing the world will take from it is this: the Americans are serious about their laws. Don't screw with them.