Get the Army on the border and set up fenched tent camps to hold the illegals. Investigate the ring leaders and send them to Gitmo. Tattoo the illegals so if they come back they are subject to being shot on sight .
I have advocated for a cheap effective way to close the border for years (crazy?): MINE THE BORDER!
Oh,, sure; put up signs and loud speakers in multiple languages. Very soon the message will not need translation, the word will spread like wildfire.
Then the only crossings will be legal gated crossings, crossings where we simply refuse to admit aliens except with legal papers. No troops on the border, no high tech surveillance... just a casual effective border patrol... no destroyed farms and ranches... no worthless uninhabitable border properties... no $20 bil wall to maintain or prop back up.
This solution is so workable that there can be no doubt that it will never be implemented... and I will be labeled a lunatic. 😇