The unions don’t want temporary visas, they want permanent. Remember the Dorgan amendment? Remember the Dixiecrat republicans voting with the unions.
What if the “temporary workers” don’t go home? I think new programs of this sort don’t help. There could be a responsible compromise, perhaps, but the plantation owners, their allies, and congressional prostitutes don’t want to have to bother with having to enforce visa exit dates. And of course, they are not concerned about allowing more terrorists slip through the cracks.