No one's saying we should have to replace them overnight. But if the program is made available only to people in their home countries, then the illegals will be replaced over time. The problem of those already here is less pressing than the problem on the border. If we get the border taken care of, then we can take our time weeding out the illegals here in the country without feeling like we're having to empty out the basement with a coffee cup in the middle of a monsoon. But we're not going to get the border under control if we keep holding out the possibility of rewards for people who cross it illegally.
We don't disagree on that. We're probably talking about a chicken vs. egg problem, but I think that if these people have a choice between a legal and an illegal way to get here, the vast majority will choose legal.
The real way I think we can get the problem under control is to make the employers responsible. They also need to have a choice between legal and illegal employees, not a choice between illegal ones or none at all.
And it will be easier to control the borders if we're trying to stop a trickle, not a flood.