Bayh didn’t quit; he is serving out his term. Hope this helps.
Bayh no doubt will be the darling of the DemocRats for the rest of his term.(/scarcasm off)
Maybe he didn't quit outright, but he's certainly a free agent now....
Small, technical difference. By not seeking the second term that everyone believed he was going to (he shocked the political world with this announcement), he is in effect quitting. Yes, Sarah quit without fulfilling her term, but Bayh is still "quitting".