IDK, but it's obviously costing much more over time for the U.S. Taxpayer to keep them here, not to mention that they're bankrupting valuable services to the rest of us.
It would keep them out if we had an effective fence that they couldn't just cut through or go around. Perhaps two much like the Berlin wall was.
It's a flawed argument to say that it's gonna cost too much. It "costs too much" with lawyers involved. If we just round them up, put them on buses or trains, cart their asses back to Mexico without having to ensure that they go in five-star, first-class comfort, then I can't imagine that it costs all that much.
But the cost to us over the long haul is the loss of our nation. Which would you rather pay. I'm tellin' ya, in 50 years you won't be able to tell the difference between certain parts of the US and Mexico. It may not even take nearly that long.
It's kind of like saying it's too expensive to treat cancer. Well, OK, but we all know that the result is if we don't.
How do you really know? Find me a link to study with comparisons okay and then maybe we can argue the point more.