It needs to be painfull for employers to hire illegals. I'm not opposed to a guest worker program after all availiable positions are filled by Americans.
There are laws that exist to punish employers who hire illegal aliens, but they are not enforced. Even if Congress passes a bill calling for mandatory 20 year prison terms for these employers, this bill is a dead letter if the executive branch refuses to enforce it. The solution to the illegal alien problem is not to pass new laws, but effectively enforce those already on the books.
We already have a "guest worker" program..
That's what green cards and work visas are for..