The illegals wouldn't be here at all...
...if American businessmen weren't hiring them because they're willing to work for nothing, and will put up with all kind of abuse from their bosses because they know they can be deported.
You want to stop illegal immigration, start punishing illegal employers. It really is that simple: hire an illegal, go to jail. No walls, no guards,
nada. And you won't even have to spend money to deport them. They'll self-deport.
Like most other problems in this country and the world, if you dig deep enough you'll find some capitalist is responsible for it.