The President has indicated in the past that he would veto any such legislation. The private sector serves a role, and will be around for a long time. The unions have attempted this over and over and over.
I assume the Feds are not as stupid as the State of CA, I hope. The BOP has been a big supporter of private corrections and actions speak larger than words by their recent contract with CXW, etc.. As fullcount1999 says the unions get some puppet representative to try and push thru legislation, but the big question these reps fail to fill in is, "where do we move the prisoners too?". The Fed has said they will add 10,000 more beds to the privates in the coming years.
Charlie Thomas has a web site where issues like this are discussed.