[inquest]

What I've been trying to say is that American employers need to have a way to make sure that their employees are legal (be they guest workers, immigrants or citizens), and that they have to be held responsible for hiring any who are not. Further, they should have a way to hire as many legal workers as they need.

That doesn't explain why there'd be any greater advantage to making the program available to illegals aliens in the U.S., as opposed to making it available to foreigners who apply in their home countries. It certainly doesn't explain how the former would be more effective at reducing illegal entry than the latter.

[speekinout]

There are currently something like 10M illegal workers in the US. There's no way that they can be replaced immediately with a guest worker program that starts with application in the home country.
Try to think about it from the view of the employers. What do you think a small employer who depends on low skill labor would do? Be diligent about checking papers, even though he or she might not have enough workers, or turn a blind eye to some marginal papers?

The problem isn't illegal workers as much as it is finding low skilled workers for jobs we really do need.