I think Andrew Sullivan's basically right about this:
There were many legitimate ways to discuss and criticize Bork's radical judicial philosophy, but the demagoguery deployed against him was a smear campaign of almost unprecedented ferocity. Ted Kennedy was among the crudest. (Wally Olson has a fascinating column on how Bork was also borked for not being a religious man.) The consequences are still with us, along with the deep polarization that event intensified in Washington. Reagan need not have nominated Bork, of course - and he deserves some of the blame for such a radical move. But the smear campaign from Bork's opponents dwarfed everything else, in my view. It helped create the poisonous atmosphere we now live in. Because it worked.
Or, as the WSJ put it:
Led by Ted Kennedy and Joe Biden at his slimiest in charge of the Judiciary Committee, Democrats and the left ran a smear campaign for the ages. ...
So nasty was the campaign against Bork that his name became a verb—to bork, as in to utterly trash someone's personal and professional reputation. For younger readers who wonder when U.S. politics took on their current poisonous character, the Bork fight was the turning point. Democrats cast the first smear.