Why is Kennedy trying to sneak through his abomination by way of an amendment? It must be he doesn't think the votes are there to either stop a filibuster or other parliamentary moves if the bill is brought up on its own.
Nah.. essentially, it was the old 'organ measuring' routine.
Sessions proposed to attach an amendment that would make it illegal to hire aliens, so Kennedy responded by trying to modify Sessions' amendment into an immigration reform package. Just the same old 'in your face' stuff that goes on behind the scenes all the time among the 'adults' running 'America's most deliberative body'.