catfish suggested:
"I propose the idea, that instead of building a wall, we build high speed rail from a few select Mexican border towns to Canadian border towns. Make it free, with the stipulation that they agree that if they are caught in the US again, they accept and face stiff US jail time and fines."
Actually, "rail" isn't needed.
Why not just provide free deluxe charter buses making the same trip?
With the same stipulations attached?