That's the big one. We need to drop the hammer on people who hire illegals. If it were up to me, the first and second offense would be a huge fine (I mean huge, like 20% and 40% of the previous year's reported revenue), and the second offense would be seizure and auction of the company and its assets.
Then when the goldmine dries up, the illegals will go home. It's like dealing with ants and roaches: don't leave food lying around so they don't have a reason to come in, and they won't.
The ones that don't leave, when we encounter them, we arrest them and deport them.