Eisenhower did the put them on the bus routine in the 50's (Operation Wetback was what it was called). It worked fine then and could do so again - with the political will to do so. It would likely cause a revolution in Mexico, which would not be a bad thing in my opinion.
That's a great point. I've long believed that the real problem is in Mexico City and Mexico's corrupt government's "Mexican diaspora" or "nation without borders." They are forcing their people here. They demand loyalty to Mexico. They meddle in our internal affairs at all levels to get that loyalty. They expect us to foot the bill. Their people are coming here with their stomachs but they are leaving their hearts in Mexico.
There is a regime change needed in Mexico City.
Now, what about the other half of ILLEGALs?
Mexico very desperately needs a revolution in order to overthrow it's absolutely corrupt federal government.