The illegals came across the border under their own power. They can go back the same way, and will if employment opportunities dry up.
Strong employer penalties for hiring illegals (fines and incarceration) would eliminate opportunities for illegals to work. This also would increase employment opportunities for welfare queens, chronic unemployed and others sucking on the government teat.
Also do some real combing out. Check out immigration papers at every traffic stop, every law enforcement encounter, every welfare/food stamp office, and every time somebody comes to a hospital seeking free care. Then deport those who can’t prove they’re legally here. That’s pretty much what happens in foreign countries to Americans. Just go to England, get involved in a traffic stop, not be able to show your passport and US driver’s license and see what happens.
The welfare has to dry up too.