Why let them in in the first place? Once they're in, they have all kinds of "rights" our founding fathers never imagined thanks to Democrats, the liberal courts and the lying lamestream media.
Don't let them in. Post "you will be SHOT DEAD if you cross illegally" signs all up and down the border, then make good on it. Plain and simple as that. Illegal immigration will stop in a big hurry once the bodies start piling up.
Then again, President Trump can simply sign an EO ordering all money transfers to Mexico be halted and watch how fast the Mexican Government starts cooperating ....
Nobody is going to get shot. That is silly talk.