"the employers who currently hire illegals in the undergrouond economy - don't want legal guest workers, they want the underground undocumented workers they have right now. and that demand will continue to be filled by illegals. "
My thoughts 100%
those workers will tend to do what their employers want. many employers do not want guest workers. an illegal who becomes a guest worker, and goes to work at Walmart - will be replaced in the system by another illegal coming across the border to fill the day labor job the "convert" just gave up.
absent strong employer sanctions and a rock solid border, you cannot break this cycle. the market forces are too strong, and the pools of people who would willingly come here, is effectively infinite.
I wish we could get some honest debate on this point, but everything is filled with cries of "racism".